Your question is confused a little confusingly, which doesn't help. But in general, a cell phone repeater needs to be designed quite differently to a radio amplifier. A cell phone doesn't just receive signal like a radio; it also communicates back to the cell phone tower.
As a result, amplifying signal in just one direction isn't very helpful: your cell phone won't work better if you have much stronger downlink without a correspondingly stronger uplink signal. Fortunately in most cases the uplink and downlink signals are split onto different frequency bands, making this slightly simpler (in contract, TDMA systems such as WiMax use different time-slots to communicate).
So you'd need to design a bi-directional amplifier with band filters that separate the uplink and downlink frequencies. Berthold Horn at MIT has a great series of articles explaining cell phone repeater basics. To get a sense of the complexity of some of these systems, you might try purchasing a unit from a cellular repeater distributor and checking the specific RF filters used to separate the uplink and downlink frequency bands.