Recovery when old WAL segment has been overwritten?

Hi folks,

Running 8.0.1 on Linux I got this in my log yesterday morning:

LOG: unexpected EOF on client connection
LOG: unexpected EOF on client connection
LOG: archived transaction log file "000000010000000A0000003F"
LOG: server process (PID 15318) was terminated by signal 9
LOG: terminating any other active server processes
WARNING: terminating connection because of crash of another server process
DETAIL: The postmaster has commanded this server process to roll back
the current transaction and exit, because another server process
exited abnormally and possibly corrupted shared memory.

However, very soon after this happened the server archived the segment
0000000100000008000000C2 which had originally been archived on May 28,
so I have only been able to "recover" the database to May 28 as my
most recent base backup was from May 26. How can I recover the data
that was written between May 28 and yesterday morning?

John Barham