I am assuming that you have access to the WP database (via your hosting phpMyAdmin), and that you can’t recover you login via the ‘lost password’ thing.
I also assume that you can access the pages of the site (the non-admin pages).
So, it would appear that you need to recreate your admin user in the WP database. This page (among others found via the googles) will help you recreate the admin user http://www.inmotionhosting.com/support/edu/wordpress/333-add-admin-via-mysql .
If your user already exists in the database, then you may just need to reset the password, again through using phpMyAdmin through your hosting account.