Hi Laurie: Whew, it IS confusing, isn't it? Lots of us feel just like you just after diagnosis, as we're asked to make all kinds of decisions, yet don't feel we have the information we need — AND we get conflicting opinions from our medical team! Take a look at our IDC FAQS for a good summary of all kinds of information about IDC.
Since you're already doing chemo, you're going through the most aggressive, roughest part of treatment right now. So you'll have that out of the way. Next, it sounds like a lumpectomy. If they can get clean margins (i.e., they feel they've gotten all of those three tumors out, with no cancer cells left around the edges of the incision), then the usual treatment would be radiation to your breast, to make sure any other "wandering" cancer cells are taken care of. This is absolutely the gold standard of treatment: lumpectomy + radiation. They go hand in hand.
If they can't get clean margins, you'll have to have a mastectomy; and then you most likely wouldn't need radiation.
Unless the cancer has spread out of your lymph node into the surrounding tissue, they wouldn't need to give radiation to your lymph nodes; they simply will remove the one node with cancer, and probably sample a few others up the line. If they all come out clear (which they probably will, given the tiny amount of cancer in that one node), then nothing more needs to be done regarding your lymph nodes.
As for radiation itself, most women find it much, MUCH easier than chemo. So don't worry about it being a really devastating experience... it shouldn't be.
Hope this has helped you out, Laurie. Please stay in touch - we're here for you. -PJH