My old 40Gb started showing the same symptoms about 6 months before it got YLOD.
If you are worried about losing data, best to act early.
Doing a backup from one PS3 and restore to another means you will lose save games and other files that are copy protected. So when my PS3 died, I was very sad about losing my Demon's Soul save and a few other savegames.
So, I paid to get my PS3 YLOD repaired, bought a slim then i used the transfer utility (and prayed the YLOD lasted long enough), which copies EVERYTHING across. I jumped for joy to have all my data.
Now my old PS3 is sitting in a cupboard, even though it works.







