Yes, the gas mileage isn't great. But it's also not a deal-killer. Just run the numbers:
12.5k miles/year @ 19.5mpg = 641 gallons. Gas near me is about $2.25, so that comes out to $1,442/year for gas.
Option 1) trade in the truck for a 35mpg car. You now spend $803/year on gas, saving $639, or about $53/month. But you don't have a truck any more. And now you've spent a bunch of money on a car.
Option 2) buy a second, more fuel-efficient car. Let's say you split the mileage 50/50, so now you're saving $26/mo on gas. But you're also registering, insuring, and maintaining a second vehicle, and those costs will probably exceed the gas money saved. Plus, you've just spent a bunch of money on a car.
Yeah, stick with what you've got.