batch is not ruined.
did you do malt extract, boil 2-4 gallons and add water at the end? If so, you can simply add more water. Try and get the water at the same temperature as your fermentation before you dump it in.
Or let it be. If the fermentation goes as planned, it will be a higher abv beer.
google "John Palmer how to brew" or pick up a copy of the book if you have not already. Its the best thing you can do to kill time while your beer is fermenting.
Welcome to the hobby, don't be a stranger on the site (its a great resource!) and of course rdwhahb