Help needed RE wraps or rent to buy

Tried posting in help forum but no replies soo…..

Hi all, I am selling 2 houses, 1 an investment, the other was our PPOR which wouldn't likely suit investors. I have advertised them on ebay and owner seller sites nd have had a lady ask me about rent to buy. How would this work?
The house is listed at $213,000, we have mortgaged to 87.85% of 205,000 so still owe $180,000 and have converted it to interest only repayments of $258 p/w, so from what I can see, her repayments would have to be rather high for her to pay principal and interest, and would we have to change back to principal and interest or do we just add up the extra she pays and take it off purchase price when she re-finances properly.
What sort of deposit would need to be paid by her if any…etc etc….would we have to re-finance (not an option as we aren't doing too well financially right now)
We want to sell to buy a business, so we would need a deposit to cover our main reasons for selling, otherwise we would just rent it out for $220 p/w and cover the $38 ourselves (now that much we can afford….lol) and are we allowed spend the deposit etc etc…..
TIA any and all info apreciated as we may even look at doing it with our investment if we need to although interest in that one is high (we actually had it sold until darn REA's talked my buyer out of it with false info…grrrr) as it returns 6-7% p/a before expenses.

Been thinking a little more, and all we need is the equity cash we have in the properties, so we would even be willing to sell to a people who wrap themselves as long as we can access this money. From what I understand some will simply take over mortage repayments etc…..problem is, both properties are tied in together on same loan. It's really annoying since I know there is interest in the more expensive house as a rent to buy but I know nothing about rent to buy!

Please…anyone who has any ideas please reply as we have a deposit on stock that we will lose if we don't get the remaining funds in 4 weeks time!