Wireless router probably which has strengh of distributing good frequency. Not wireless b/g
compatible router. Also you need wireless extender in case range is not enough till 29th floor. I have some experience in Wireless. But
outdoor 5~6 km distance strengh wireless equipement not actually a router. RADWIN is famous in Wireless. Check out RAD's web site.
Cisco also have many cool wireless products which r catagorised under "Linksys" but i am not much familier with Cisco's wireless router's.
Regard's,
Amey Abhyankar.
[ If your budget is low, look for NetGear's wireless router. Cheaper in cost and good at
performance. ]