extra things also
1) On HOME computer - allow Remote connections - set up in control panel and allow in router / windows firewall / AV software - allow PORT FORWARDING as the previous poster says.
2) On your HOME LAN (even if you only have 1 computer attached to your router) you'll have to give it a fixed INTERNAL IP address in the network properties -- such as 192.168.0.47 or whatever range your router uses.
Note when you set this up you'll have to enter the Gateway (usually the .01 address at the end of the addresses your router uses -- in the example here its 192.168.0.1) and the DNS's your IP gives you -- if you don't know these use the ROUTER status when you get home before you change your home computer to a static IP INTERNAL address.
3) Port forward in your router (as per 1) to THIS address (192.168.0.47 or whatever you assigned)
4) check that you can PING to the EXTERNAL address that your router presents to the Internet.
(Do this from OUTSIDE your LAN - use your mobile vodafone connect if you are at home).
5) ensure that the outgoing ports at work aren't blocked -- some workplaces block RDP ports so if that's the case you'll have to use Tunneling -- I'm not listing how to do this this here as it could be considered a security Hack in bypassing a firewall although its a legitimate process.
(As your on Vodafone mobile - this shouldn't be an issue as this works fine normally -- that's the whole point of data cards - to be able to connect remotely).
If your IP gives you a dynamic IP - most do these days then you have two choices
Make sure you have the IP address before you leave home --although these could change.
Or use a FREE service like no-ip.com - Google Search
THis is MUCH better than paid for stuff like log me in etc as you get a domain - you don't even have to use the domain as from work you can logon to the no-ip site - check your database and see what the IP address is at any time.
(Some workplaces also block sites like log me in anyway).