I presume you're talking about amplifying the transmit side . Yes , amps are "frequency specific " to some degree .While modern amps are fairly broadbanded , there's a big difference in the requirements between 27MHz and 144 MHz .You can find a bevy of 2m amps designed to work with your HT at the Mirage website , www.mirageamp.com
, or check the AES , HRO , or other ham store websites .Check the ARRL bookstore or your local club for reading material that'll give you a deeper understanding of the technical stuff . The more you learn , the more fun you can have .
Russ , W5RB