*Router:
Router if you want secure and good wifi router Zyxel is one of the better ones. It is worth its weight in gold almost. As far as I know it has good support and recent updated unlike linksys that stops after 2 years to update their stuff. But read the reviews and do some homework.
http://www.newegg.com/Product/Product.a ... 6833181218
*Powerline network adapter: 200mb/s
Also check power line network adapters as this you only need a lan cable to this wall plug device and same on otherside in apartment / flat no drivers to worry with.
http://www.newegg.com/Product/ProductLi ... rder=PRICE
*Pci cards any atheros / broadcom should work but you might get a good deal on a packeged bundle say a linksys router + 1 or 2 pci cards.
Newegg.com / zipzoomfly.com / outpost.com "fry's electronics" will have these and Fry's has specials on on fridays for the weekends if in USA.
I have the wrg54gs with speedbooster linksys router and like any routers in the last 2 years it has removable antenna.
*Distance in B mode is about 250Feet + and for G mode is a bit more narly about 150Feet.
*Apparently if you can get a good 802.11N router + 802.11N pci card you can get something like 270MB/s over 300+ Feet not sure have to check the specs.
I check retail websites for specs and reviews , make a list form 5* to 3* I would like and then ebay it to get a normal decent price.
Try also shopzilla.com and pricewatch.com as alternative to ebay.