[VPN Giving internal IP?]

Sorry for the delay! Potentially, if you were natting your public IP as opposed to using something like Dynamic DNS.

[VPN Giving internal IP?]

The reason you can connect internally is because your VPN is still only seeing the inside network. You may need to look at your actual router. You would need to do port forwarding and/or network address translation on the router so that the OpenVPN servers IP address is available to the outside. 

Keep in mind though, that when you do this, your exposing your internal network directly to the outside world without the protection of NAT or the firewall so make sure you read up and know what you are doing before moving forward.

Realistically and statistically, you will be fine. But there is always the chance.

[Super computer ideas?]

Like haze1434 suggested, you could build something that distributes the workload over multiple devices. Look into something like a Beowulf Cluster.