You said you had many active lesions in your last MRI. It seems to me, that whether you've had MS 7 years or 1 year, if you're provided with an effective drug to inhibit the inflammatory response, the body will be allowed to repair the myelin and return function.
I have been really disheartened reading about your rapid decline from someone pretty functional to someone struggling with everyday normalcy- it strongly reminds me of my own rapid decline over 2 years. Just 2 years ago, my MS was not recognizable walking down the street. Before I went to Hopkins I could barely walk even with my cane. So, I hope you find something fast to turn it around for you.
Perhaps I am more of an optimist for you than you are for yourself. As much of your decline was recent, I feel there is great hope for a good deal of recovery. Whether it is tysabri or rituxan, I feel you will get good results. But, be aware that you will be very open to infection with rituxan. The severe reduction in b-cells poses potential for on-going risk.