you can trap them and transport them, if you don't want to shoot them,
you can buy a trap for $20-30
when we had squirrel problems, it seemed you'd hear them, then go in the attic and they'd be gone.
good luck!
I think in most states you can shoot squirrels year round.
I'd seal any small holes you can find, they make that great stuff foam in a rodent formula... quick easy option,