Welcome to WordPress.com! The short answer to your question is 'yes', you can use your domain to point to your new WordPress.com blog. This is called domain mapping. To use your domain at WordPress.com the first step would be to change the name servers of your domain with HostPapa to:
Based on posts by other HostPapa users you will need to contact their support to make this happen. Keep in mind that you will still need to pay HostPapa for the domain registration for as long as you wish to own it. You can transfer the domain registration away from HostPapa to another registrar, but that's another problem altogether.
Once your name servers are changed, you can move to the next step:
After the name server change takes effect, go to Store -> Domains in your blog’s dashboard, enter the domain into the form at the top of the page, and click the Add domain to blog button. If the name servers are verified, you will be prompted to pay for the upgrade and complete the process.
After the purchase is complete, go to the Settings -> Domains page, select the radio button next to the domain you just mapped to your blog, and click the Update Primary Domain button.
Check out the tutorial here: http://en.support.wordpress.com/domain-mapping/map-existing-domain/
Let me know how it turns out!