I agree with Nigel. At these frequencies your chances of successfully designing and building a receiver are close to nil.
On the bright side, you can get there eventually, but it takes considerable effort and patience. You did not say what modulation modes you are interested in and since the frequency range includes cellphone, GPS, government and other bands you need to have some idea what you are listening for.
In addition you need to think about antennas. No one antenna will provide adequate performance over that frequency range. There certainly is alot to deal with.
If you have the time and the patience you might consider looking into amateur radio resources. Not only could you find receivers for 900 Mhz, 1296 Mhz and 2.4 GHz, but transmitters as well.
Check it out.