Hi -
It's possible to collect stem cells again, but not as quickly and easily, usually, as the first time. I had enough for 3 collected at one place and ended up having more collected at the place where I wound up having the SCT done. Maybe your treatment center doesn't want to have to store them for you. I know that many other places have no such policy, so if there's anywhere else you'd consider going, check with them.
Have you joined the mailing list? Lots more people are active on that list, and you'll get more replies.
http://www.mmsupport.net/content/view/188/80/
Beth