Mr. Tribalgooseeb:
The party has two strikers, a controller, and two leaders. The best thing you could do if you like filling gaps is play a defender. Otherwise, I'd recommend you play a controller. In general we recommend people play what they want, but again the party's greatest need is for a defender, if you're into helping out the needy.
You probably shouldn't play a gnome because the group already calls itself the Gnome Punters, though I'm not convinced they put a lot of thought into that name.
We use the standard point buy system and I *think* you'll be starting at level 6, which is the median party level. (I don't remember what level Billy's at...if he's somewhere around 5th then I might start you off with roughly equal experience to him in the interest of fairness.) Plan your character for 5th or 6th level.
On Fridays, Rick is usually the first one in the shop and is clearly visible by his SFIV headband, which I assume he'll never take off now that he has it. Then again, the Sox are playing again so you'll probably find him wearing a pair of headphones in the back of the store. He can probably help you smooth over any of your character details until I arrive at the store on the 17th.
Game on!