A booster is generally what you'd use to boost your signal. If you are trying to speed up your connection from far away, then this may be helpful. However, no matter how fast you want your Internet to go, it's all up to your provider and what their bandwidth maximum is. For instance, if you have a 60mbps connection and want it to go faster, you'll have to call and ask for a better plan because nothing will really help it to speed up.
One thing you can do is make sure you're not using Netflix and things of that nature on more than one device if you're having slow speeds. I have 2 kids that are always streaming videos, and if one of them gets on Netflix, all of our connections seem to get slower. It happens to be known as the largest bandwidth hog and I assume a lot of connections seem slow due to people streaming video.
If you're trying to boost a signal from one room to the next, it may be a good idea to just get a better router. I was able to find some boosters on Best Buy's website that may help, but again they won't do much to increase your bandwidth.
My suggestion is to get a better router that can handle more information and connections. Find a more pricey one that allows you to set maximum bandwidth usage across your devices, and that way you're able to control how much everything is using. You can then set it up to be faster on one device when it's watching movies, while being slow on one you're just browsing with at the same time.
1 - http://www.gamepolitics.com/2011/05/17/netflix-biggest-hog-bandwidth-trough