How can I repair a towel rack that was ripped out of the wall?

Since you already have a wall paper finish on the wall and you are hesitant to move the towel bar to another location this does put a damper on the types of solutions that could be used to fix this problem. By the way; Don't feel too bad about the failure. It is very common to find towel bars attached just into the drywall. :-(

The normal "robust" way to fix this would be to make a hole in the drywall near where the mount ripped out of the wall. Such hole would be about 2" (5omm) high by 4" (100mm) wide. A piece of wood with string around its middle would be placed down into the slot and then raised back up inside the wall using the string to pull it back up so that it was centered over the opening. A 3.5" (85mm) wide by 8-12" (200-300mm) long board would be used for this. Holding the board in place with the string, you would install drywall screws through the exiting wall board and into the wood to hold it in place. Patch up would consist of cutting a small piece of new drywall to fill in the slot hole and screwing it in place. Drywall taping, mud and sanding would be done to finish the wall back to a nice finish so that it could be re-painted. With this scheme the towel bar support can now be re-installed using longer screws to reach into the wood support that was added. The wood support spreads the stress of the towel bar across a much greater area of the wall preventing future tear out.

Now that you have a picture of what could be done let me suggest an alternate approach that will provide a strong support and permanent fix. For this you would remove both towel bar brackets and install a primed and pre-painted horizontal board across the wall in line where the towel bar mounted. You would secure this in place using screws into the nearby studs. If the towel bar was mounted in a narrower wall segment it is best, from a looks standpoint, to extend the board across the width of the wall. After the board is mounted in place the screw holes would be filled with spackle, sanded and touch up painted. The towel bar is then mounted onto this painted board.

With this latter approach it may be desirable to size up the room and if there are other towel bars present you may want to install these board strips in a uniform manner for those as well to maintain a style in the room.

If you saved some of the original wall paper it is also possible to glue wall paper onto these strips after they have been primed. Done carefully the wall paper pattern can be matched to the wall and make the towel bar mounting boards hardly noticeable.

A quick and reasonably sturdy solution is to use plastic drywall anchors or toggle bolts.

They are cheap, easy to install, and hold around 50 lbs+ per anchor. So if you use 2 per end, you're looking at ~200 lbs capacity. Not enough to do chin-ups on, but good enough in my opinion. Plus you can probably install them in the same location as the pulled-out screws without requiring any patching.

I had a similar problem in that a towel rack was ripped off a hollow door. I didn't want to get a new door, and I'm not big in the tools department. What I found was a very simple DIY way to fill in the holes which worked surprisingly well: toothpicks.

The origin of this solution came from another question, asking how to fix stripped screw holes. Just put in some toothpicks with plentiful wood glue. After it dries it's surprisingly strong.

What I ended up doing was a bit more involved, since it was a hollow core door rather than anything particularly deep. But the principle is the same.

1. Shove toothpicks into the hole until you can't fit any more.
2. Apply wood glue around all of the toothpicks.
3. Snap off the ends sticking out. I used a utility knife to clean it up.
4. Wait until the glue is dry.

I was able to reattach the towel rack in exactly the same position, and it ended up actually being sturdier than before.

I don't know how well it is going to work, but I was able the whittle down a cork from a wine bottle until it was fairly snug, I then drilled a small drywall anchor into the cork and attached the mounting bracket to the cork. It feels fairly sturdy, but time will tell. Hope this helps

I used rulers. I premeasured and predrilled holes for the mounting. Next, I added holes in the ruler above and below the properly measured holes. Through the above and below holes I strung gardening wire. I used ample wire. I cleaned up the hole with an exacto knife. At that point I slid the ruler into the wall through the hole (just large enough for the ruler to fit). Be sure to hang on to the wire ends for this step. Next, I lined the holes up with the opening in the wall and began getting the rack anchor screwed to the ruler. You can pull back hard on the wire to get the screws to attach as you turn the driver. Before you tighten things all the way down, you will want to patch what you can with filler. I didn't need anything, because the rack brace was large enough to cover the entire area. Tighten the hanger all the way down, nip off the extra wire that is showing and finish as usual hanging the rack.