if the revision in your title block is taken from your idw iProperties then you can put the revision value into the iProperty directly.
if you place a revision table on your idw then right click on the table and choose "add revision" then it will bump the revision in your iProperty and at the same time you will see your title block update.
if the title block defenition does not read the iProperty then you can edit the title block definition, edit the rev text within that, and add the value to read from the idw iProperty.
try to just hit F1 (help) for more information whilst ininventor and while in the command, or search inventor wiki help for some more info.
Inventor 2014 Pro on Windows 7, 64bit
(please give Kudos or Tag as Solved if your issue is resolved)