Well since you're trying to attract women to your party, you need to make it sound like a party girls would want to go to. 12 horny guys and a keg in a beach house does not sound like an appealing party to most women.
1. Make girlie drinks. Can any of your friends bartend/mix drinks? That's what women drink. Look up a couple good recipes online for mixed drinks (lava flows, long island iced teas, fuzzy navels, etc etc) and buy supplies accordingly. These drinks are not hard to make, and add class to your party and your friends.
2. Have a theme to your party. Have a beach theme, or a superhero theme, or a costume theme, something to make it more than just a gathering of people for drinking. It makes the party more interesting and gives the girls a reason to go since it's not just an ordinary party.
3. Make it seem like a lot of other girls are already going. Again, girls don't want to randomly show up to a party with just 12 horny guys and a keg. That's not fun for them. Downplay how many guys are in your party and talk up how many girls are coming. Have your most social/handsome guys already there at the start of the party. They are the bait and the hook to make the girls want to stay. Have your other guys (with less social skills and less charisma) arrive periodically through out the night rather than just having all 12 of you there waiting expectantly like hungry wolves waiting to devour the girls.
Send your guys out. It can't just be one guy recruiting for a party. Have all your guys actively working to get girls to come. Your guys I mentioned earlier that are supposed to arrive later? Have them canvas the local bars picking up women there to bring to the party.
4. Finally, it's better to have one really good party at the end of the week then to have a small disappointing party every night. Use some nights to plan and organize your party so that your party will be big, fun, and exciting.
~Antithesis