You can block the bad country traffic though by using .htaccess and I think cpanel has a way to block specific countries from accessing your site.
But I wouldn't block the traffic just so I could use media.net I would just wait it out and keep doing SEO and overtime your website traffic should start coming from the USA.
For targeting US traffic search for sites based in US or having more US traffic. Leverage following off-page optimization activities to get traffic on your website:
1. Leverage social bookmarking sites like digg, delicious, reddit etc.
2. You can leverage some forums and participate in discussions.
3. Also you can use Questions/Answers sites and share your website link as reference link.
4. You can also submit your blog links on some blog directory sites
5. You can write some Guest posts and give reference links of your website in Guest Blog content.
6. Share your website link as reference link on good article sites like ezinearticles.com
7. Submit the RSS feed for your blog.
8. Leverage social networking sites like FaceBook, Twitter etc. for sharing your posts their
9. Leverage Linkedin as well for writing and sharing blog.
10. Post some Infographics on your blog and share them on sites like SlideShare.net etc.