There is nothing wrong with using the transmitter and receiver you obtained. 72MHz is still a very useful item and will work very well. You will (at least should) replace the batteries in the transmitter and the one used in the plane for the receiver as batteries that old can be suspect. While getting a nice new 2.4GHz set would be nice, if you are watching your pennies, nothing wrong with the tried and true old dual conversion 72MHz units. If you are insistent on a new system, the best buy for your money right now might be the Tactic TX850 as you can get that with an 8 channel receiver for $159 from Tower Hobbies and additional receivers are quite reasonably priced. What for coupons and save another 10 to 15 bucks. The Tactic will work well with the servos you mention.