You could talk to ten different people and get ten different answers.  A lot depends if you have a window at the shop facing the house.  If you do no outside antenna would be needed.  Without it you will need an outside antenna.   I would use two Linksys WRT54GL routers and one WAP54G access point.  What I like about these is they are good stable radios and can be loaded with 3rd party firmware with which you can double the output power.

Put one router at the house and the access point and other router at the shop.  Put the access point in the window to receive the signal from the house and run a network cable to the router in the shop.  The router at the shop would provide the signal to your laptop.  No window, then use an external antenna on the access point.

If you aren't very computer savvy then you should probably get a local computer nerd to help. This stuff ain't rocket science but it can get confusing.  If you look back in the other threads that covered the same subject there are some good links with good info.

Edit:  You could get by with just the access point in the shop if you have a window in the shop, by setting the access point in the window to get the signal.