Hi Jess,
At the moment, there is no way to push your ad to the top without deleting it and creating a new one. Some people actually do that, and you're welcome to if you have the patience.
Sometime down the road I may add the ability to push ads to the top by renewing, but if I do, it will come with some sort of required waiting period (30 days?) to prevent the aggressive types from dominating the ads.
Regards,
Jonathan