Missing WAL files - file-based replication

So we're using 8.3 with file-based replication using rsync to a warm backup
server. The problem is the backup server crashed and somehow WAL files got
lost so the backup server is continuously looking for WAL files that are no
longer available on the master.

My question is, how can I skip to a set WAL file so that the recovery
process can start ingesting WAL files again? I realize there's going to be
a certain amount of data loss but that's not as important as getting the
backup server processing log files, in other words I don't care about the
data loss.

There are approximately 20 WAL files missing. I've tried to find out where
pg_standby keeps a record of the current file it's trying to restore but I
can't find any information on where that information is kept.

Can I use pg_standby NEXTWALFILE in the restore_command to do what I'm
trying to do? And if I hard set NEXTWALFILE, will pg_standby still
automatically increment WAL files it's ingesting when it finishes the hard
set file?

Thanks!