Are you using a scanner and a separate 2 meter radio? If you are try Ham Radio Outlet, or one of the other ham radio vendors, and check the specs on a duplexer for what you want to do. If you're planning on using both radios at the same time this might be a viable option. If you're not going to use both radios at the same time you could try an antenna switch, which will be cheaper.
If your ham radio has enough memory you could use it for scanning as well. I've had good luck with a Larsen 5/8 wave 2 meter antenna before. Has very low SWR on 2 meters and does good with VHF public safetey monitoring too. If you mount it on a Jeep make sure you have a good counterpoise for it. If not, you could try a half wave antenna as they're not too dependent on a good counterpoise.