Blog Posts pushing down right-column widgets

hi there y'all -

I've been fiddling with this for a bit - if I tweak the css for .content to a fixed width of 660px then the right-column widget on the home page stays put but if I leave it at width of 100% then when I post something it pushes down the widget.
also, oddly enough, if i change the css to 660px (as above) then when i click through to the post itself now the css has moved the blog sidebar widget around.

in any case, any suggestions? i saw the previous hack in here somewhere about dropping a background image that helps extend the bottom of the right column to match up with the footer so you get a nice border - i was prepping to do that next... I suppose that would at least give the right column a clear visual separation from the post content but all of the right column widget content still gets bumped down by the post.

help me jeebus! (or, preferably one of you knowledgeable peoples)

my apologies if this has been answered elsewhere - please direct me to the answer if that is the case!
thanks!