Congrats, sounds like your first brew. If so, welcome to the hobby.
Just as an FYI, there is a lot of good info on the beginner's forum on modifying Mr.Beer kits. Mosly, it involves replacing the added corn sugar with additional malt extract, and adding extra hops to the recipes. Also, playing around with fermentation variables like ferm temp can also alter the taste of final product. Hope you enjoy the porter and keep brewing.