I purchased a new, agitator and easily replaced the broken one. No tools are required. If it does not release easily when pulled, you may want to loop a tie down strap under each side in a sort of figure eight, in order to gain added purchase. Mine did not require this, but there is a video on YouTube that shows this method.
Now I must repair my other 15 month old GE washer, which is stuck between cycles. Hopefully it is just a clogged drain. My appliance repairman's' experience has caused him to not bother with the new GE washers. He says that they are 'Junk!: