Incremental backup with RSYNC or something?

Hi.

I currently have a cronjob to do a full pgdump of the database every
day. And then gzip it for saving to my backup drive.

However, my db is now 60GB in size, so this daily operation is making
less and less sense. (Some of you may think this is foolish to begin
with).

Question: what can I do to rsync only the new additions in every table
starting 00:00:01 until 23:59:59 for each day?

Searching google leads to complex things like "incremental WAL" and
whatnot, or talks of stuff like pgcluster. I'm hoping there's a more
straightforward core solution without additional software or PHD
degrees.

Many thanks for any ideas!
PK