If you want a bit of reading material as to good spells in general take a look at this:
Clicky Clicky
It's meant for wizards, but some of the stuff can be applied more generally to arcane casters as a whole. You just have to be more choosey about what you get.
The "artillery" role for the party isn't really to hard to fill. At low level you'll be just as effective, or more effective (with an 18 dex), using your bow than with your spells. A 1d4+1 magic missile just doesn't do much at level 1. You'll have to find a balance between getting the newest shiniest attack spells are getting spells that are otherwise effective.
I find that damaging spells are not really where it is at. Battlefield control and strong buffing spells are a whole lot more helpful in my experience. In that line, Grease, glitterdust, haste, mass fly, wall of stone/force, solid fog/freezing fog, Evard's Black Tentacles, Howling Chain, and others. A main prospect when choosing spells for a sorcerer is how much you can get out of them. It's nice to have spells that can serve multiple roles.
When I do go for damaging spells, I try to avoid those that require a save if at all possible. Yes, you will need something like fireball for area of effect reflex save damage, but in general I find it much easier to use something like scorching ray or orb of cold than to have an opponent fail a reflex save. Saves start to outpace even the most devoted evoker's saving throw DC after a while. I'd be loathe to toss a fireball if my group had as many melee guy's as yours will. Haste's average damage output would far exceed the puny 6d6 you'd get out of a fireball.
My favorite damaging spell are:
Scorching Ray
Defenstrating Sphere (Complete Arcane)
Fireball / Scintillating Sphere
Firebrand (SC)
Ball Lightning (SC)
Orb of ____ (SC)
Many Jaws (SC)
There is a fun spell called "Unluck" that might suite your concept of a gambler; you might want to check it out (Spell Compendium).
As a sorcerer you are feat starved, especially going into a prestige class that requires 3 feats for a sorcerer. You'll need to pick a metamagic feat as a part of that requirement, I'd recommend sculpt spell, and then pick up empower spell later when you have more feat slots to use it.