rider_ :
I now have a large antenna, an access point (disabled dhcp and can access wirelessly), and a router, routing the dsl connection. How can forward the free wifi using the antenna + access point +router?
I assume your access point is for your personal in-home wifi? Is the router just a plain router, or a wifi router? I assume it's a plain router since you have a separate access point.
1) Talk to your workplace about this first. They will probably be OK with you using their Internet from home. They will probably NOT be OK with you repeating their Internet over your personal wifi. Many, many security break-ins are caused by people (usually clueless managers) sticking an unauthorized wifi access point onto the work network, and not properly securing it. If you do this without asking them, and they end up getting hacked and find out you're how the hackers got in, best case you will be fired, worst case you will be sued and liable for all the damage they suffer.
2) Depending on their OK, you will have two choices.
2a) If they say you can use it but no additional wifi, then see if your access point has something called client or bridged mode. This will allow it to act as a big wireless adapter. It can connect to a wifi network, and anything you plug into its LAN ports will be able to connect to the wifi network.
2b) If they say sure do whatever you want, and you want to keep your personal wifi, then you'll want to get a separate wireless bridging adapter. Don't be put off by the name - usually it's just a wifi router which supports client/bridge mode. They used to be a separate product, but wifi routers sold a lot more and economies of scale lowered their price to where they were cheaper (same reason they don't sell WAPs anymore). Since you already bought an antenna, you'll need to get one which uses the same type of connector. If you hadn't gotten the antenna, usually I recommend the Ubiquiti Nanostation Ms over short haul links like this, since it's pretty reliable, cheap, and is an all-in-one solution.
https://www.ubnt.com/airmax/nanostationm/
When set up, it will act as your router (swap it with your DSL router depending on which source of Internet you want to use). It'll just be getting its Internet from a wifi hotspot instead of a physical wire.
Optional 3) If you want a more "seamless" transition when switching networks, you will need another router. The DSL or work wifi router will plug into this third router's WAN port. If you don't have this third router, your network will go down each time you switch Internet sources. Regardless of how fancy you get with this option, certain Internet connections will go down when switching (secure stuff like banking) since the switchover changes your Internet IP address. You will need to login to various websites again. All this does is prevent the switchover from messing up the movie your roommate is streaming from your in-home media server.