I have Verizon DSL service that came with a westell 7500 wireless router, but the wireless does not cover a big enough area.
I also own a linksys wireless router which I would like to place about 75 feet away, up one floor, in order to have complete coverage for the building.
It seems it is not as simple to simply plug the second wireless router into the network, it shows up as a wireless router, but if I connect to it from a laptop I can't get to the internet...
What is the basic steps I need to take in order to inexpensively add a second wireless access point to my network? I don't mind if I need t omanually pick one wireless point versus another, but it would be better if it was possible to just log onto either one and have the laptops talk to whichever router is available.
I'm not sure about the standard Linksys firmware, but DD-WRT supports AP mode. You could use your Linksys router as a secondary router running in Access Point mode, though I think you might have to connect the two routers via wire as opposed to wireless.
You mention both routers and access points in your question. An access point bridges wireless media to wired media (with many optional bells an whistles, too, on a real access point). A "wireless router" provides access point functionality along with additional functions to route TCP/IP between subnets (and provide network address translation, etc). I don't think you're looking for a second TCP/IP subnet and routing between it and your existing LAN subnet. I think you just want an access point, and you can use another router as a cheap access point.
Go get a second wireless router, and configure it as follows:
We've done this fairly frequently with one Customer who wanted access points "on the cheap" by using Linksys WRT54G wireless routers and, through the procedure above, effectively disabling their "routing" functionality and just using them as wireless access points.
Alternatively, if you want to spend a little more money go get a wireless access point that doesn't have router functionality. It will need less configuration but will be a little more expensive. (Market dynamics are at play there... There's less demand for low-end access points than routers so the price of an access points ends up being higher than a router even though an access point "does less".)
The DD-WRT suports Repeater Mode, just take the other SSID and spam the coverage..