The least expensive thing to do would be to get another receiver and use the transmitter from your PTS. There would be nothing at all wrong with doing this. If you really enjoy the hobby though, plan on staying in it and don't mind spending the money, something like a Spektrum DX-7 will work well for years to come.

For an engine, something like an OS .65-LA is an inexpensive, reliable option that will work well. The .61-FX is another good choice. 7ou could also invest in something like a .75-AX. It is WAY more than the plane needs but could be useful for something down the road.

I'd just use plane old, inexpensive standard servos such as Futab S-3004, JR ST-47BB, Hitec HS-325, etc.