iPhone stuck in boot - sleep button stuck in

Went to reboot my iPhone yesterday and it got stuck in the boot mode. Usually this wouldn't be a problem; I'd just reset it with the power and sleep buttons. However, my sleep button has been stuck pressed down for a few months now (out of warranty).

I've tried running the battery down, same problem. Is there any way I can force it into DFU or recovery mode or something from a computer or without the sleep button? My phone is basically a useless glass brick at the moment.....

Thanks!