Hi flowerflo. Have you been referred to physio yet? If not, get your midwife to refer you. When I was pg with DS1 (6 years ago) my fantastic physio recommended the Stokke Xplory and I have to say it was worth every penny my mother spent on it (I was extremely lucky)!
Although it was heavy to get in and out of the car, it was fantastic all the rest of the time. It was a walking frame for me, very sturdy, but could carry loads of stuff. The pram (baby bag I think they call it) bit was great for the first six months as I'd just wheel the pram into the house and park it in the dining room with DS1 still in. Then I didn't have to try to get a sleeping baby upstairs to his cot. If he was in the car he was in the lie-flat Jane Matix car seat which just stayed there as I couldn't lift it in and out. I'd then just slide him gently from car to pram and he'd often stay asleep. Once we turned it into the pushchair both boys loved being high up and facing me as we could have long chats. In fact the only time I turned it round was when we went to restaurants and they didn't have a good high chair!
The best thing to do is to see if you can 'test drive' it as you will get a feel for whether you think you can manage it.
Re the cot, make sure you get one which can start off high, but can be lowered as once babies are on the move they can get out easily! I know of some which have three height levels. Also make sure it has one side which can drop with one hand.
I would also recommend the Stokke changing unit. It is big and bulky, but it was, again, for me worth every penny. I used it day and night for both my boys and it was just fantastic not to have to get down on the floor.
Do PM me or chat more on here. I know I probably haven't been very clear!