Any reputable lender can score you on a pre-qualification, they can then TELL you what you would need to do to enhance or increase your score, in most cases a 620-640 score will get you in the door with a prequal ... based on what is actually in your file ... I DON'T recommend credit repair companies, your score is what it is and those are usually short term fixes, in my opinion, and cost money that may not be a wise expense .... work towards getting a solid score that will stand the test of time... you DON'T want it to bite you in the "you know what" when you are getting ready to close and change the deal...
Anyone that post's here is a qualified RE agent... I don't post lender info... I have solid contacts with some that I do business with every day and can put you in touch with them ... they can all help.... good luck!
All Real Estate Options, Inc.