Below are several you may want to check out.

Personally, I'd never leave a pet alone for a few days. Hopefully you're going to have someone check in on her daily while you're gone.

Here is a link that might be useful: cat feeders

My brother has tried a couple, as has my sister. THey both report problesm with the timers not working correctly (power outages can throw off electrical ones). Sarah's stony figured out that the timer had something to do with the food and whacked on it until it went off! THey have also had issues with the cats prying up the lids. This is why the only automatic cat feeders that work reliably are called "friends".