How to calculate repayments in order to pay off a personal loan by a certain date?

I have a small personal loan ($3000 remaining).

The current interest is about 15% (per year???, charged monthly) but I also have to pay a monthly service fee ($10).

My current weekly repayments are set to what I chose at the start of the loan, and at this rate it will take about another year to fully repay the loan.

I want to repay my loan by a certain date (April 30th 2020), and I want to know how much my repayment needs to be to pay it back by that date.

I’ve tried some loan calculator websites, but I haven’t found one that allows me to enter the monthly service fee ($10) into the calculation.

How can I calculate it (what is the formula? or where can I find a personal loan calculator that can do it for me?), and what does my weekly repayment need to be to pay back by that date?

I know there are some other factors such as these:

1. It’s a variable-rate loan, so the interest % might change
2. There are fees payable if I go over the yearly repayment threshold
3. Depending on my personal financial situation, it might make more sense not to increase the repayments

But I’m happy to ignore them because it’s such a low amount and I’m just looking for a ballpark weekly repayment amount to pay it back within about 4 months