Yep. Your beer is going to be weaker than you wanted. The only thing I can think of to try is to quickly brew a gallon or so of a higher gravity beer, and blend it in.
Two Kids Brewery
Primary: nothing. :(
Seconary: Don't use one, generally
Kegged: Belgian Brown Ale (loosely based on Corsendonk's Brown Ale); Saison
"For a quart of ale is a dish for a king." - Shakespeare