I had an ankle replacement due to bone on bone arthritis when I was in my 20's. I also now have plantar fasciitis to deal with.
I understand how hard it is to walk when in pain. I used to be a triathlete before my ankle problems.
My advice:
1) rocker sole shoes are amazing! (try MBT's or Sketchers have some cheaper options - make sure they fit snugly!)
2) use nordic walking poles when you go for a walk (best with rocker sole shoes). It helps take the pressure off the legs and makes it much better to move. Added bonus is it also burns 40% more calories.
3) get a hot/cold pad. Heat the sore joint/area before the workout, cool it after the workout.
4)Biking was easier than walking for me. Try renting a exercise bike for home that you can use (or go out for a bike ride is much more fun) Google the 39stonecyclist, it is a really inspirational story about a guy and his bike =)
5)Tiger balm or deep heat type stuff helps with the plantar fasciitis, rub it on the soles of your feet, sit down, and put a golf ball under your foot and roll it around, get it in deep and it's like a massage. Really helps me. Also doing the stretches for PF at this time are good.
6) treat yourself to a foot massage every now and then (if you can).
7) go swimming/ aqua aerobics etc etc. Honestly as someone who was super fit and tiny, we don't look at fat people as much as you think we do at the pool - you may feel uncomfotable - but we pretty much live at the pool it's pretty much the same as seeing you fully dressed to us. Also if we do happen to notice you, we are more likely to think, 'good on her' than anything else. So don't let it stop you.
Ok sorry for the novel but hope it helps someone!