Fiber Glassing is really not that hard to do.5 or 6 oz cloth and thin or thinned epoxy. Tape a piece of cardboard covered with wax paper over the opening to act as a mold, paint on a layer of epoxy, place in your fiberglass cloth (enough to extent about 1" outside of opening you are filling) paint on more epoxy on top of cloth until wet, squegee off exess. When fully cured (allow 24+ hours) remove cardboard/wax paper (some will stick, don't worry) sand and fill with automotive spot puty, sand again until you get a nice smooth surface, Prime and paint and you will never know the hole was there.
Even a small package of fiberglass cloth will be way more than you need so a practice run on a piece of scrap wouldn't hurt.
52 size 4 stroke is equivelent to a quality 40 size 2 stroke.
Magnum makes a nice one, Tower has them for $130 and if you look around you may find one for less.
http://www3.towerhobbies.com/cgi-bin...?&I=LXAN93&P=0