Welcome to MyFICO! 
How much are you putting down for down payment?
I ask this because even if you were to get your mortgage mid score to 620 so you can qualify for a conventional loan, the interest rate and PMI, if applicable, would be extremely high.
If you are putting down 20% or more, than you don't have to worry at all about PMI but the interest rate will still be very high.
If you go FHA rather than conventional your interest rate is lower and your MI is lower making your total payment lower. By the way, the MIP rate for an FHA loan is .0085 per year with 3.5% down. If you put down 10% or more for your purchase, the MIP drops off after 11 years on an FHA loan. Otherwise it stays for the life of the loan.
Here is a chart from one of the PMI companies so you can see the matrix that shows the relationship between qualifying score, interest rate and LTV and how it affects your PMI rate. As an example, with 3% down the PMI is 2.25% annually (3x's FHA's rate) with a qualifying score in the 620 to 639 range. If you are putting down more, then the rate is reduced. See the rate card below for details. There are only a handful of PMI companies. One caution: you might get approval for your loan subject to approval for PMI and the PMI co might say no. Talk to your LO about your options.
