If you haven't already done so, click on the "Trade Skills - by Trade" link in the column to the left. This will give you a list of all the formulae available for enchanters. Those with formulae written in white are available from vendors - click on the link to find which ones. Just glancing quickly at the list, there seems to be one available at 265 in Winterspring, one at 280 in Moonglade, and possibly others.