Global Find/Replace for Assignment titles or descriptions?

I am changing from an in-line HTML formatting of color and size of assignment titles to a CSS that uses span and class instead.  Is there a search and replace operation I can use or am I stuck with going to every entry to type in the same information for each?  If that is not possible, can I place information into every description easily?  I can see how that would save me a lot of work too.

I am backing up in 2.5.1 and wonder it it could be easier to do it there first or wait until the restore into 2.7 is done.  I get the feeling that it may not matter.