Remember the FHA fees: 1.5% of the loan amount into the closing. 100,000 loan for example brings 1500.00 into your FHA "fee" closing cost (on top of all the other closing costs).
1/2 a percent is the cost of MIP (mortgage insurance added monthly to your refi). This stays until you reach a 78% loan to value (request it removed at 80%). The MIP is held for a minimum of 5 years (regardless of the LTV). So again on a 100,000 loan for round numbers, 100,000 x .005 = $500.00 (divided by 12 months = $42.00 a month for the mortgage insurance). So including all costs monthly = Mortgage payment + FHA Insurance/MIP + property taxes.
With credit an issue, FHA may be your best option, but check with local lenders/brokers. There are online places, but check locally first in my opinion. You may not have to do a FHA even, but even if so, they can still give you an idea of what your payments would be and all that shiz. Watch the points and closing costs. They add up and depending on how much your refi is, they can be a substantial amount of your total loan % financed. But sometimes a refi can be a necessary evil.
Hope I got all that right. Double check it
LL