Posting an add in the personals section or having a pretty profile is not the only or best way to attract a female dominant.

You need way more exposure than that.

Posting frequently and meaningfully in a wide variaty of places in the forums as well as participating in an adult and respectful manner in chat can help a lot more.

Attending functions within your local scene is also a good idea.

And as ian mentioned, you never know when you will find a woman out there who may feel willing to fill your needs.