Correct me if I'm wrong, but the excess of 7430 positions more than the available positions is for all residencies, and not only exclusive to primary care. In Fam Med for match year 2007; out of a total of 2603 open positions, only 2299 filled (88% fill rate); page 29 of the NRMP report. That's almost 300 Fam Med positions that remained open last year. 46% of the filled positions in Fam Med went to IMGs, compared to 42% to US graduates.
This is not to say it isn't difficult for IMGs to match, who have about a 50% non-match rate overall. But I would argue that the difficulty in matching is not the availability of spots, but applications with problems (300 open positions after the match in Fam Med seems like relatively large number). Assuming the OP is an US IMG, those 300 spots would represent ~1/3 of the 1300 unmatched US IMG applicants last year.
The greater than 5 year duration since graduation the OP disclosed makes the above moot. But looking at the PGY-1 Prelim surg match data, only 62% of spots are filled, leaving approximately 700 spots open. If the OP could find a program that wasn't so anal about his/her graduation date, good clinical letters and evals from a PGY-1 year would go a long way to getting a clinical residency.