Gnomish Ballista

Gnomish Ballista

STR 13
DEX 18
CON 14
INT 14
WIS 14
CHA 7
LUK 12

You can go Ranger -or - Warrior as this class.

Feats: Just like an Elven Ranged Ranger, go Point Blank Shot, Defensive Shot, Aimed Shot, Far Shot. Then whatever you would like.

Either will let you use the Cranquin as your main weapon, which is normally an exotic weapon.  It is a large crossbow like the arbalest, but has a better threat range, does an insane x5 damage on a critical hit, has a very fast base attack speed, will stun a creature on a critical hit or 1 in 3 attacks, and grants x2 bonus to penetrate armor.

Gnomes carry it in both hands - you're also proficient with the mercurial broadsword, so you can pick one up around the dungeon and use it as melee in a pinch.  Generally you're better off using the cranquin, which can oneshot many enemies point-blank.  Since you're a gnome, you receive a quick loading cranquin, and you receive the rapid reload feat at level 1.  This combination represents the pinnacle of crossbow use in the game.  Unfortunately, you're a bit squishy, so it can take some finesse to survive the early game.