what are you doing to get your B12 and folate up? And did they check your copper, zinc, Vitamin D and B6 levels also. These all play a critical role in blood production. Your B12 needs to be over 500.
Your B12 is low and needs to be corrected.
IMO, fix the nutritional issues before attempting ATG.
And as hopeful states, make sure you are treated by someone with lots of experience with blood disorders. And a second opinion is always a good idea.
Here's a thread on a study regarding low B12. You can do a search to find more discussion on it.
http://forums.marrowforums.org/showthread.php?t=2507