I think this is what you are asking for:
1) Rent: Your annual rent will be $7800 ($650 x 12)
2) Gross rent return: Annual rent ($7800) as a percentage of buying costs ($10,900 assuming that $2900 + 8000 reno is needed) = 71.55% ($7,800 rent divided by $10,900 x100)
3) Mortgage repayments...