I would explain to the store about your condition and how hard it was for your hubby to do it alone. Explain that in hindsite, you would have the couch delivered to your home and are willing to pay the $75.00 delivery to get the "new" couch if that was necessary to have them swapped at your home. Or, I'd get a good friend and offer pizza/beer after the couch was set up! Something! The deal is, you spent a reasonable amount of money on this couch (it wasn't free, right?) and you want it to last for a while (at least 5 years or so) and if you keep it with the tear, and it gets worse (especially with a little one crawling on it, finding the tiniest of holes and poking his/her sweet little finger through it!) you won't have any recourse with the store. I say suck it up and get what you paid for! But, be willing to pay the extra $75.00 for home delivery if necessary. I would try to bargain, explain, plead, beg the store to do the delivery to the house or store first, but if they were firm with "you ordered it to be picked up in warehouse and that's where you have to get it" then I'd be willing to pay the $$. However, I would expect them to work something acceptable out since it's not your fault that there is a tear in the merchandise. Had there not been a tear, you would not be having this conversation, so it really falls on them to remedy it in a manner acceptable to you!
Good luck! Don't keep the ripped couch!