Help! My shop just been hacked!

[Pascale]

Hi,
I haven't been working on my shop for a couple of months now and I've just had the unpleasant surprise to find it's been hacked "just for fun"... you can see what I mean on www.beauluxe-bike.com
It's my first shop, and I was more concerned about how it looked than how secure it was... to be totally honest, security issues didn't even enter my mind... I wish I had read that useful post before :
http://www.prestashop.com/forums/viewthread/40862/security/security_101__is_your_site_protected
I guess I'll be more careful next time... learn the hard way...
Anyway, what's the next step, do I erase everything and start from fresh or is there another solution?

Thanks

Pascale