Find out what similar homes are going for in the area. Look in the newspaper and call the landlords to see what they are charging. Drive the neighborhood and note "For Rent" signs and call on them, too. Regardless of what was paid for it, the appraised value, or what remodelling was done, you probably can't get too much higher than market rent.
Do you know how you are going to screen the tenants, how much to look for in income, how much for the application fee, who's doing credit check, etc?
One other thing: you stated in an earlier post that your mortgage is $1400/month. If both sides rent at $770, you could be in in a negative monthly cashflow situation, especially if taxes and insurance are not escrowed into that monthly payment. Have you calucated your costs?