I am Homozygeous for the MTHFR gene (c667t). I am also homo and hetro for a bunch of other stuff. In order to work out what was what I had to do a whole load of reading, and I understand totally your confusion at this point!!
I can tell you that being hetro usually means that your pathways are functioning at up to 70% (for homo it is more like between 20-30%).
www.heartfixer.com/AMRI-Nutrigenomics.htm is an excellent place to find put the information you are looking for, but it isn't an easy read.
Basically, for a MTHFR mutation you should be investigating the use is Methyl B12 and Methylfolate (NOT Folic acid!) That said, because you are hetro rather then homo, you may find that a very small amount of supplementation is necessary, some don't need it at all - that's due to the interplay of your different genes and possible mutations.
You should also be aware that over use of these supplements can be as problematic as not taking them at all, particularly methylfolate, who's side effects are very similar to those you can experience from Lyme (Read up here -
mthfr.net/methylfolate-side-effects/2012/03/01/)So, I take 1/5th of a 3000mg Adensyl B12 supplement (I take this rather than methyl B12 due to other mutations) and 1/5th of a 1000mg methylfolate suplement, daily.
Did your doc test for other gene mutations? I ask because these may have a bearing on what you may need to supplement with and in what amounts. I had mine done through 23 and me, but I had to figure out what to do about
them without the help of a doctor