Tires Tires,

I'm gonna assume you wanna keep the 13" wheels, and the 5 on 4" pattern (personally , I would move to 15s, but wheel selection is almost non-existent)
Go to TIRESIZE.com and hunt up the tire size calculator chart for 13"wheels. It will tell you every size 13 available give dimensions and height, if you want to go bigger/taller.. (ranked by height 21,22,23,24 inches tall.)
If you can use a 24" tall tire, I'd go a 175 or 185 80 13. If that's too tall, a 185 70 13 is an inch shorter.
Any size you want, Walmart can get.