Unique 5/5 situation

[StupidAcesSigh]

So I was playing a 5/5 NL game which at times got down to heads up against me and the drunk russian. I was faced with what was obviously a hugely profitable situation and am curious what the optimal play is.

With effective stacks of $900, my opponent would blind raise to $50 or $100 preflop. He would do this in either the small or big blind. Since small technically acts first, this is obviously only allowed in the small position, but I can't imagine anyone would make a fuss over it :P

So how do you deal with this raise? Push or fold? What hands are you pushing with? For situations where effective stacks are $400, $800 and $1000 and with blind raises of $50 or $100.