Well, if you choose to go on a vps or dedicated hosting plan, will be easy to add a static cache on nginx and in your database, take a look qt these sites:

http://www.6tech.org/2013/02/nginx-tuning-with-php-fpm-and-m...

http://pureform.wordpress.com/2008/05/21/using-memcache-with...

And, if you can fit redis at this setup even a very small vps would handle more traffic than a shared hosting