Since you don't know what you're dealing with, it's best to have a Professional do the job. You may even need a new cement pad. Since you'll be hiring a Pro, consider moving it to another side of the house all together! 2 feet vs. 20 feet, what the heck??? Of course, consider the neighbors and if you'll get noise with windows open on whichever side of the house the unit ends up on.
My best to ya and hope this helps.
Jay J -Moderator
PS: There are 'chemicals' involved in this move. Please don't attempt to do this on your own.