After RAT POISON/ANTIFREEZE...How do i rid my yard of squirrels?

You should remove and dispose of (securely) all the poisoned bait, before you kill (or kill more of) your neighbor's pet animals, directly or through ingesting poisoned squirrels. Likewise the predators that would help you by eating squirrels, if eating squirrels didn't kill them because the squirrels were poisoned.

Removing the food source is the very first thing you should do to reduce squirrels.

The only "reasonable" approach to killing them (other than selectively hunting them) is to trap them in a live trap, so that you can release any birds or your neighbor's dogs/cats that inadvertently get trapped, and then kill the trapped squirrels as humanely as possible. [Transporting them elsewhere is often strictly illegal, and generally does not work.]

You cannot selectively rid your garden of squirrels. It's not possible.

• As noted by others, poisoning them also poisons everything else including large birds of prey that feed on them. If you see any dead hawks, owls, or eagles within a mile or so of your property assume you did it. You may also be killing your neighbors' dogs and cats.
• Trapping / Shooting or other forms of killing squirrels in a suburban environment is a bad idea. First of all, squirrels breed and they move around. Unless you kill all the squirrels within about 100 square miles of your house (and almost all other wildlife with them) you'll be unsuccessful. And there are animal lovers who would unhesitatingly kill you if they see this stuff. The normal thing to do with squirrels after trapping them in a cage is drown them in a bucket. Are you going to do that in front of your neighbors? It's not worth it.
• You can make your garden less attractive to ALL wildlife be removing things that attract them. Don't feed birds. Cut down trees. Don't plant anything. Each step you take towards making your garden look like the inside of a concrete prison cell, the less you'll attract wildlife.
• Or go the other way: Embrace it. It's very hard to make bird feeders squirrel proof, and squirrels will always feed on the stuff dropped by the birds on the ground. But you can make the feeders more difficult for squirrels to access, and by doing that, you can arrange that the birds get 75% of the food and the squirrels 25% rather than the other way around. Then enjoy watching it all unfold like a scene from an old Disney movie.

My advice: Learn to love them.

Here: Here's a deer, a turkey, and a cardinal. I hate squirrels too, more because they get into my attic than my garden but anyway ... it is worth enduring all their mischief for rare moments like this.