When to take a stand?

[fnurt]

$50 NL tourney on Stars. Down to about 50 players and I have T1800 which puts me among the smallest stacks. Blinds are at 100/200 and going up to 200/400 soon, probably in the next orbit.

I am dealt A8o in the BB. Folded around to SB who raises to T600. SB has about the same stack size as me (I barely cover him). I don't know much about SB, seems like a normal player.

Obviously there's a fairly large range of hands SB will raise with here. Equally obvious is that I'm going to have to take a stand sometime soon and try to double up. The question is, is now the time?