(...once they put the sigs feature back in)
Locate a post you had made before the Forums change. Highlight any long sentence part and copy it.
Google that sentence part ("with quotation marks around it")
Below the link will be a cached version of the page, in which you'll find your old sig. 
(...once they put the sigs feature back in)
They started with signatures, no need to put them back in =)
Check out 'Preferences' (top left)