Wireless Lan Card outdoor Antenna

hi i have designed Wireless Network in our town but problem is comming that users with indoor builtin antenna with Wireless Lan Card are having signal problem in their home in the room...

All i want that i want to design outdoor Antenna for my Wireless Lan Card then install it on the roof

is there ny cable available which works as 2.4 Ghz Antenna which could be install on the roof

or ny cheapest way to design wireless antenna.

Thanks

i want to know the performance of this

"Tin Can Waveguide WiFi Antenna"

would it be applicable for my Wireless lan Network

i want study papers based on this type of antenna.

thanks

mmmm no one has used this antenna ?