It looks like a whisper 100 or Rena 400 or Whisper AP 300 would work. I have one each of the little ones and they've all gone a few years with no issues. See if this page helps.
http://pet-supplies.drsfostersmith.c...&subtotal=0.00
http://www.drsfostersmith.com/produc...fm?pCatId=3676
Do you have a air compressor, like a 1/4 horsepower one for paint or nails? You can use that for fish in a pinch.
Go get the biggest aquarium air-pump wal-mart sells tonight and shop around for the best replacement until it breaks.