What kind of VPN is your work using? There may be a client out that will work. The problem may be the dynamic IP, depending the VPN. Usually it's just a matter of configuring the client and having an account.
Are you trying to access your work computers from home, or your home computers from work? Or both? You can have a dynamic IP on the client computer, but not the server. Therefore, you'll probably be able to access your work computers from home, but not your home computer from work. There are a lot of specifics to this topic. It's not as easy as well all would want it to be. Ask your Network Admin. at work to help you...if you have one. He SHOULD understand how to make this work.