First, you should get rid of all the nuts and food that is in your yard or it will keep coming back. Second, if it has kids, wait until its away to get rid of them then put mothballs at strategic place. The odor will kip it away. Third, you can go to http://www.squidoo.com/howtogetridofsquirrels for more tips on how to get rid of squirrels.
Every time she leaves the pot to feed, move it a few feet until it's off the porch into the yard somewhere. Preferably near some trees or shrubs. Tedious but the other option is to get rid of the babies altogether. Not a nice thing to do. (Or call a pest service. They will remove them. But again, it may mean death for the babies.)
Don't..enjoy observing her and being that close to nature...we could learn a lot from the instincts of squirrels...they know how to take care of themselves and prepare for tougher times ahead...its worth a small inconvenience.