Nancy, one more program to help you with 100% financing is the Texas First Time Homebuyer program through the Texas Department of Housing and Community affairs. You can read more about it here: http://www.tdhca.state.tx.us/homeownership/fthb/down-payment-assistance.htm
That link will also help you find a list of lenders approved to offer the program (like us). I know of a few lenders in Texas that can go down to a 580 on FHA and utilize the Bond 77 program for 100% financing. If you would like me to refer you to them, let me know. We require a 640 or higher.
That being said, I would work on getting your scores to at least 620 for FHA. If you want to put 5% down then you can go with Conventional financing and you will need at least a 680 or better; not a 740 but rates are credit score sensitive on the Conventional side so the higher the better.