You will also need to install the IIS feature - since accessing RDP via the web will be done via a Browser. The remote browser will also need to have ActiveX authority as well so I don't know if you could use Firefox or another non MS Browser.
(I'd prefer to use the "Bog standard" RDP connection rather than use the web specific interface -- but YMMV of course).
In both cases ports and firewalls need to be configured to allow access.
On your HOME router port forward 3389 to the internal Lan address of the computer you want to connect to.
Use something like No-IP if you need a FREE dynamic DNS update - you'll need this type of program if your ISP uses dynamic IP addresses. http://www.no-ip.com