You will need a good holster, like a BladeTech or CompTac or Safariland, not a cheap Uncle Mikes, and a good belt, like the Wilderness Instructor or Double Alpha, not a Wally World dress belt, and at least 6 magazines and mag pouches, not Mecgar cheapies, good 1911 mags, like McCormick, Tripp Cobras or Wilson Combat. If you have any money left over, get some electric ears. Contact the match director before you show up, some clubs require a full day training session before they let you shoot. The Grand Masters make it look to easy running $5,000 Open Division guns, but there is really no difference between you and them, except they do pistol fundamentals (stance, grip, sight picture and trigger control) about 10,000 times better, and typically have well over 20 years of competition experience shooting over 60,000 rounds a year.
So, shoot fast and have fun, but prepare to be humbled.
Check USPSA.com for more information and club listings.