So the room should be dim
That is, I am sure, part of the problem. The darker the room, the brighter your monitor appears. That means that, when you're toning, you're actually making the image files darker than you would if you did the same with the room lights brighter. That means dark prints. This was a huge issue when LCD's started replacing CRT's and there was a lot of complaining about dark prints.
My advice, beyond getting a screen profiler which is a MUST, is to turn on the room lights. You don't want to make it too bright, but you will want the light to be closer to average room light. The actual brightness is going to take some trial and error on your part, but eventually you'll get to where your profiled monitor more closely matches your print output.
As an example, I do all of my work in a 7 foot by 13 foot office lit by two 60-watt bulbs (actually, the cfl equivalents). It's much brighter than my monitor profiler recommends, but it works perfectly.
As for the ColorMunki vs the EyeOne Display, the latter only profiles computer monitors, while the ColorMunki will also help profile printers, as well. I've never used the Munki, so someone correct me if I'm wrong.
Chuck