Increasing AP strength/laptop wifi strength

I have a toshiba mp50. The AP is a netgear Rangemax 4-port wifi. The problem is that the building has too many concrete sections, and there is only one area that has AP. Is there anything I can do to increase my laptop wifi or the AP signal. I prefer a low cost solution for the AP site, since its the company. I don't mind a mediocre solution for the Centrino laptop. Will a directional antenna a plate of aluminium foil work? Thanks

The AP is the new Netgear rangemax wifi with 4 ethernet port. Its just a machine, no antenna sticking from it.

<A HREF="http://www.newegg.com/Product/Product.asp?Item=N82E16833164105" target="_new">This thing</A> kix rear. I never thought that 50 bux can replace $600 1W setup.

..this is very useful and helpful place for information...