Backup/Restore to a point in time

Hello,

1) I know that Postgresql writes its transactions to logs (WAL).

If I take exports once a day (say 7am) and I have a client that somehow ruins their database at 5pm today and it is now 7pm, can I somehow get the database back to the state it was in at 4:59 (right before they blew up their database)?

2) Where are the WAL files located?

Thank you!

~ Troy Campano ~