I understand the uniqueness of the character and it will definitely be useful to have someone with above-average proficiency at close quarters. You are right however. Something to protect yourself at range would be a good idea.

 Hmmm... in terms of weapons you might want to look into a handgun, a compact smg or, in your characters case, an automatic shotgun.

I assume you at least know a little about handguns so won't present an example.

The [url=Uzi Pro]http://www.israel-weapon.com/?catid=%7B89B2D388-821D-424D-B8AB-CB619D165202%7D[/url] is a good example of what to look for in an smg. At just 12 inches/30cm long and being very light it'd be easy to conceal and its rate of fire and size make it great at close quarters.

An automatic shotgun would be devastating at close ranges but their effective ranges generally max out at about 50 or less metres for short barrelled versions (which have the upside of being more likely to hit and having the potential to hit more than one opponent at close ranges). This seems like a good fit for your character. Theres a list of existing auto shotties at the bottom of this page [url=http://en.wikipedia.org/wiki/Automatic_shotgun]

Note. A gun is not essential. As I said it might be interesting having a character who, for whatever reason didn't start with a weapon and had to pick one up in game. You may well find some of the weapons you'll be facing early in game would suit your character and you could always borrow one.