RE: what to do
Post pictures of the PT-40. You'd be amazed at how badly a trainer can be built and still fly well. The SuperSportster is a good second plane, but I personally wouldn't want to use it for training a beginner.
$200 for engine and radio equipment is not out of line. I picked up a Hitech flight pack a few weeks ago at the LHS for $80, and a good 46 can easily be had for rougly $100 (just don't go with OS, YS, or Saito. Think Thunder Tiger Pro or Super Tiger.
Brad