hypothetical loan situation

[kurosh]

Currently 20k is loaned out. 5k will be repaid in 45 days. another 5k will be paid in 90 days. After that, $500 will be paid every week until 24k total is paid off.

The borrower would like to loan another 20k with a similar sort of $500ish/week payment deal until x amount is paid. The cost for the lender to get this 20k to loan out is 1k. The lender can achieve 17% annual return through his own investments.

What amount should the loaner ask the borrower to pay for this extra 20k? I'm thinking maybe 50k or 52k total in $500/week payments after the initial 10k.