Looking for WiFi solution

[HandofDeath]

So I live in a 1 floor condo and I'm having some internet problems. The condo is shaped like an "I", just one long hallway connection all the rooms. Of course, the modem and router setup is in one end of the hallway, and my computer is at the other end. As expected, I have a bad connection to my computer. I use one of these little things (WiFi range extender) you plug into the wall "http://accessories.us.dell.com/sna/productdetail.aspx?c=us&l=en&s=&cs=04&sku=A5183482&dgc=ST&cid=293344&lid=5616479&acd=12309152537461010&ven1=sE1inYhPj&ven2=", and the connection is bad, floating at around 2 megabits per second. If I didn't use it, it would barely work at all. I also have high gain antennas on my computer and router which help a little. I don't want to move the modem because the TV would get a bad connection and that would require hiring guys to drill holes in my wall. I also don't want to stretch a visible Ethernet cable across the whole place. Are there any products or methods I could use to extend my WiFi range? The connection I have is inadequate and I would like to fix it.

Update:
Thank you guys for informing me about pass-thru powerline adapters! I found this model: "http://www.newegg.com/Product/Product.aspx?Item=N82E16833181309&cm_mmc=SNC-YouTube-_-NETV-_-nMmpYjOnx1w-_-N82E16833181309" and I wanted to hear your thoughts on it and if it would work in my situation.

 

[BadActor]

http://www.newegg.com/Product/Product.aspx?Item=N82E16833181534

 

[USAFRet]

Powerline (as mentioned above), or if the residence is wired with coax for TV...MOCA devices. Pretty much the same, but instead of pumping the signal through the house wiring, it pumps through the house coax.

WiFi is absolute last on the list of connection types.

 

[jrrdmchls]

Powerline adapters are pretty nice. A better router with a better range might do the trick. I personally use this router and it covers my house completely (which was built in 1918). TP-LINK TL-WDR3600

http://www.amazon.com/gp/product/B008RV51EE?psc=1&redirect=true&ref_=oh_aui_detailpage_o09_s00