Unnecessary files that can be deleted/moved in cluster dir?

I have a little problem, I let my drive get too full.   And then while I was deleting rows to free space, the auto
vacuumdidn't kick in quite the way I expected, and I ran out of space entirely.   So the DB shut down and won't start
backup. 

So is there anything ( other than the logs in pg_log) that I can delete, or move temporarily, to save some space and
allowthe database to start up and finish it's vacuum? 

Or is there a way to move some of the stuff to another drive?  The whole cluster is too big to move entirely to a new
physicaldrive (the machine is in another city so I can't just plug in a USB drive or anything, but I can put stuff on
networkshares for now) and there is nothing else on the partition other than the cluster. 

Thanks,

--
John Abraham