If that $300 from U-Haul includes installation, that's not too bad - otherwise, it's a rip-off. There are several different hitches available for her '07 from eTrailer.com
ranging from about $150-$200 or so (plus shipping) - but you'd have to install it yourself (or pay someone to). There are links on there for plug-in wiring kits too - which will run you another $40 or so. I bought the Curt hitch and the T-One wiring kit for my '09 reg cab 5-lug 4-cyl 5-speed and am very pleased with both. The hitch install wasn't bad - but it did take a little longer than I expected. You really need another person to help you do it too.
The 5-lug is rated to tow 3500 lbs. I tow my 17' bowrider boat (weighs roughly 2500 lbs. with fuel & gear) with mine and it handles it just fine. Check out the Towing forum on here for more info. Lots of people on here tow stuff with 4-bangers.