First, read and internalize Kawasaki's "The Art of the Start" - about $20 with shipping and handling. Develop your ten slides, then try that in front of every audience you can think of. Imagine yourself on Shark Tank and try to role play each of the inquisitors, or get your friends or others to do that. There are many non-fee advisors in my area - incubators, university projects, and government-related business development. Most metro areas have the same. Find them and pitch them.
It sounds like you may have done some of that already. Are you certain your business has compelling investor value? Why can't you clearly communicate that?
If you still think you need to pay for assistance, check out Chris Shipley - http://www.cshipley.com/ Take that as the gold standard, and compare others to her. Offer payment contingent on success - they get paid after you deposit the check from investors. Ask the prospective helpers for references of others they've helped who were funded. Also ask for references of those they helped, but who did not get funded. Have a nice long chat with each. If actual value is evident, I'd offer a flat fee you can afford or options that vest at a later liquidity event.- not a percent of the raise, unless they are absolutely essential to making the deal.