I am currently playing a beguiler6/assassin2 who uses a rapier, soon will use a sleeve blade, and a Comp longbow.

Human, sneak, and arcane spellcaster of the group; He needs to be able to keep himself alive (only 17 AC ) and still be able to dish out a bit of damage, not just wait for our dragon shaman to come around to me and finish up the baddie.

I've seen the different weapon discussed here and I'm wondering if I took the best option. Should I try to talk the DM into retraining for another weapon or go "as is"

stats are
STR:12
DEX:17
CON:13
INT:16
WIS:11
CHA:14

I also have combat expertise and improved feint for what they are worth.

I've got most of my spell focused feats so if i need to take a feat or two I might be willing to do so, but you'd had to really sell it for two