Restoring Widget

Had something a little weird going on yesterday, I'm sure it was down to my noobieness....

Had a theme setup and working fine 'Blogs-MU'.

Decided I'd try and mess with the Framework/Grid theme for Marketpress.

Got that sort of working then decided it wasn't what I wanted so switched back to Blogs-MU. On switching back it dropped all my widgets back into the inactive section, so I had to go through and put them back into the sidebars. No big deal, however, when I went to the live site, the Global shopping cart widget, which had worked fine before, now appeared to have a CSS problem, the widget was overlapping with the page area by around 100 pixels or so.
Couldn't fix that so I stupidly deleted the widget, thinking it would drop back into inactive and I could reconfigure it.....of course now it's gone completely!!
Can anyone tell me how to restore that please.....feeling rather silly but there you have it!