Go to SofiTel and ask any shop for Wi-Fi repeater / Wi-Fi expander..... I would personally suggest "Linksys Wireless-G Expander".....

http://www.linksysbycisco.com/UK/en/products/WRE54G 

Also there are many other small devices which u will get for around QAR 90-120, with USB connectors, but can be used only on a single computer at a time....