As Alison said above - join the facebook group - it is wonderful!
I can only offer my advise about Tysabri. Its been brilliant for me. The Drs say it doesnt improve anything that has already happened - but I think they are wrong! I couldnt walk without support when I started (Feb 2010) and now I walk around like no-ones business!! I am JC+. It depends where you are as to your hospitals stance on this. I am treated in Southampton and they have no problems if your are JC + they just keep an extra special eye on you. I think I read that there is a new blood test which doesnt only say if you are JC + or - but also tells you your levels so you can be better informed about the chances of PML. The whole group I am in for my infusions are JC + so you wont be alone if you turn out to be.
But for me personally being on Tysabri has changed my life and it would take alot for me to give it up. (although I am about to try a break as hubby and i want to have a baby) but I will stop Tysabri when I get preggo and go straight back on as soon as I can if we are lucky enough to have a baby.
I dont know about lumbar punctures as I never had one - I was diagnosed within 78 hours of my first relapse and after 1 MRI, but I am sure someone else can give you some info on them.
I dont know if my ramblings will help you ro not - I hope so.