expanding my wifi range

Okay first you have to know the distance, second putting your eyeball where the Internet Access Point is (from your service provider) and look directly at the direction you want to have the signal go to. This second point take a pen and paper, now write down how many walls, doors whatever exists between the Internet Access Point and the maximum range you want the signal to reach.

These two are the most important factors in determining how to make this succeed. If you have (for example ) two brick walls to go through, getting a single simple repeater won't cut it. The more and thicker the number of materials and the distance between areas determines how best to 'plan' out the extenstion. Here is a chart both (http://en.wikipedia.org/wiki/IEEE_802.11) in Feet and Meters to give you the distance the signal can reach in the BEST scenario possible. You should deduct 5-10 Feet (sorry I don't know Meters to well) for each Wall / Door / etc. a signal goes through.

I would professionally hand sketch a layout of the Internet Access Point, number of wall/etc. the point most I want the signal, then draw to scale the ranges and layout a circle for where your current Wifi reaches and the size circle around the maximum wireless point. That will tell you if you need say just one repeater, maybe five? Maybe with the number of walls it be better to run a cable between points and you would drop from one hub, then reattach on the new wireless point when your in that room. There are many variations.

The newest signal is call 802.11ac, which will sit right next to the now to 'expire' 802.11n standard (g/b aren't used except by legacy devices and should be replaced as soon as possible). ac give longer range, more devices to be on at the same time, and faster signal (won't change how 'slow' the Internet is) between devices in your house. I would suggest, as your taking this point forward to have your network, to invest in 802.11ac devices (adapters, routers, range extenders, etc.) but it all depends on the distances, layout and mnumber of 'things' the signal has to penetrate.

You might want to think of it as shortwave radio, the closer to the signal with the less things in the way the better it sounds, same for Wifi.

Yes that is one solution depending on the range you need. This will give you something around ~200 ft or so @ 2.4 ghz depending on obstructions.
You would be looking specifically for an Access Point to connect to the current WiFi router and extending it via ethernet cable.

http://dx.com/p/portable-2-4ghz-802-11b-g-n-300mbps-wireless-wifi-repeater-ac-100-240v-107457
Will work for your existing WiFi signal and extend it to other areas in your house. (repeater mode) So no need for wires. You can optionally use a wire (AP/Access point mode) instead if your existing wireless router doesn't support forwarding. This will also mean that the speed will not be reduced by half due to repeater mode limitations.
Keep in mind though, that repeater has EU specification plugs.

You will need a Cat 6 ethernet patch cable to use it in Access Point Mode:
http://www.monoprice.com/products/subdepartment.asp?c_id=102&cp_id=10232

The Access point mode will be connected like so.
Internet Modem -> ethernet cable -> Existing Wireless Router (WAN Port) -> Port 1 of Existing wireless router -> ethernet cable -> Repeater/Access point -> wireless signal -> PCs

The repeater mode will work like so:
Internet Modem -> ethernet cable -> Existing Wireless Router (WAN Port) -> Wireless Signal -> Repeater/Access point -> wireless signal -> PCs

The linked repeater supports: IEEE 802.11. b/g/n (which is the current standard protocols and they are backward compatible)
The next generation is currently 802.11ac which was just recently released. So you more than likely do not have it, again backward compatible if you did.