|I didn't understand clearly how you are setup right now when I first read your original post and replied.|
How does the antenna on your home connect to your PC? Is it a wired, or wireless connection?
If wired, you could indeed use ICS (Internet Connection Sharing) to provide internet to your home. You would require two network interfaces and you would enable ICS on the one connected to your antenna. The second would be plugged into your home router.
You'd have to do some adjusting of IP addresses to get it all to work, but I think it could be done.
If your antenna connects to your PC wirelessly then your best bet may be to buy two SOHO antennas (for example take a look at EnGenius equipment) and use that to do a point-to-point wireless shot from work to home. In this case, you would have your antenna's connected to your router at each end.
I've never played with one of those extender type antenna's so I'm not exactly sure how they work.