Hmm I just looked at some pictures of a Pathfinder online.If your Pathfinder has a tire rack on the back ,that would be a spot to mount an antenna of some sort,maybe a 4 foot fiberglass whip type,such as a Firestick 2 for example,or mount a small plate for a base loaded antenna of some kind,a Wilson 3k or 5k for example.
Or maybe if your Pathfinder has the rack on the top you can mount an antenna on it if you can get the mount grounded to the body without much trouble.There are monuts that I have seen in various ham radio catalogs that will swivle around to the point that the antenna will be laying down to allow you to drive low clearance areas.
I
am sure there are other options out there,those are what I could come up with off teh top of my head this early in the morning
As far as your range out of a moble goes, that will vary with the antenna type,power you are running if any ,area you are in,if you are on a hill top or down in a hole,city or out of town areas,buildings make a huge difference as to how well you can get out, and conditions on the band (if there is high noise levels ,skip and so forth) as well as the type of set up the person you are trying to contact has( if they are moble,base....so on) SWR isnt an issue on your current set up,1.5:1 isnt anything to be to worried about.
10 to 12 miles moble to moble
AM mode,no extra power on avarage isnt to bad but can be better of course.
Also if you could post the type of radio you are running,power output of radio,if you are running extra power,output of that would be nice as well,that would give us a bit more to go on...thanks !!