Okay, I got a chuckle out of you!
I think Muppet has it. You have right now, just the receiver for the hitch. You'll need the hitch and ball and it will slide in there - they make it that way so it's interchangeable if you need to change your ball size or type of hitch.
Your owners manual or the side of your where your manufacture sticker is will have the weight capabilities of your SUV. Use it as a loose guideline. My truck is rated for 9000lbs but I would prefer not to haul over 7000lbs. Any trailer will have it's weight (on the same manufacture sticker like your truck) to compare, leaving weight room for horses/tack/feed, etc.
Depending on whether your driving something like a Jeep Liberty or Chevrolet Tahoe is going to greatly affect your weight ratio.