If you are only receive small amounts of Traffic then some key elements on your site is obviously a problem.
Rather than spending money on Purchasing Traffic you should first address why you are only receiving 3,000 visits. It is possible to get lots of traffic without engaging in traffic buying Schemes.
Ensure that your SEO is good but not over done. Your pages should generally have 400+ Uniquely written text (NO COPY AND PASTE) be fun to read and contain plenty of images as well as good page description, title and headers.
Rather than buying traffic based on Impressions it's generally best to use paid traffic based on Clicks as you will find that people who link generally want to see the content behind the add while impressions is simply giving them a chance to click.
The best way to improve visitors is to write awesome content, I know so many people don't believe this but the more pages with quality content you have then the more people that can find you and the natural link building occurs. With few pages or thin pages your reducing your chances.
If your willing to depart your cash on getting people to your site you should look into getting blogs and professional content writers to provide you with articles that can increase your rankings. I consider this by far one of the most affordable and effective routes. Just ensure they are not providing you with spun content.