That sounds almost word for word what happened to Elvis! His limp got worse, we were told hips, he went down in the front yard late one Saturday night, emergency trip, told it was knee, etc.
First, I'm so, so sorry.
Secondly, the TPLO was the BEST THING we have ever done for Elvis. Looking back we think he partially tore his ligament sometime back in the spring, and then it completely tore the Wednesday his initial xrays were done. We hadn't realized how lethargic he had become (we thought it was because this summer was so freakin hot) until 2 weeks after his surgery when he felt so much better. He's seriously like a new dog again.
We went on and build a ramp for him off our porch since he has 3 stairs to go down. He already stays on the main floor, so we didn't have to worry about any stairs inside the house. He already loves his crate, so we didn't have to worry about that.
Since he got the 2 plates and 10 screws he had a longer, slower recovery than most. He had surgery on a Wednesday and stayed at the clinic until Sunday, so luckily he was already walking on his own when he came home. They gave us a sling, but we only used it once that day to get him out of the car. He kept his cone on for 10 days whenever we weren't watching him - so anytime he was alone, in his crate, and overnight. We were lucky that he didn't mind it.
I know I've said the word "lucky" already a million times, but we really were. He could not have recovered any easier. He loves his crate. He didn't mind the ramp. He ignored the cone. I pray your recovery is as smooth as Elvis'!
Get Ronnie's rehab schedule. We didn't need it since Elvis is the least active dog on here, but I know others have found it extremely helpful. Also, search forums on here for other's experiences. I can't tell you how valuable all that was to us.
*Oh, but edited to add that his recovery schedule was like this: Only outside on a leash to do his business for the first 4 weeks. After that, he could go for one short, slow 5 minute leash walk a day. At the 8 week mark he could go for a 10 minute leash walk. At 12 weeks he was considered cleared for all activity, but again, this is Elvis so a 10 minute walk is pretty much full activity for him. We do let him out in the yard with us now while we're doing work like putting up the lights, but he stays right by me and doesn't go running around. We're still using his ramp. We're not going to let him out loose for the first few snows (whenever that may be) because nothing turns him into a puppy like snow. We just played fetch with him for the first time earlier this week - but after 3 fetches he was done. So, even though he's technically cleared, we're going slow with it for a while longer.