You can spin up another server then use 'simpleproxy' to forward ports over to the other server. This is the only way ive found to get multiple IP's on a droplet. Just set up what you want on the other ip onto a port, then on the other server proxy the port the program needs to the port its set up on.
apt-get install simpleproxy
Usage (run this command, i recommend running it under crontab)
simpleproxy -L 0.0.0.0:80 -R 0.0.0.1:8080
Forwards all connections from 0.0.0.0:80 to 0.0.0.1:8080, the first ip (0.0.0.0:80) can just be the port to move any connection from port 80 to the other location (0.0.0.1:8080).