AirPort Express or Extreme? So I'm no expert when it comes to advanced internet knowledge and I need to update my Wi-Fi router. We have 14 megabits (I think, no pro at this) or something and I have my room in the floor right underneath it and with our current router it's very slow and I called my internet service and they said I should upgrade my router since it's 5 years old.

I figured I wanted to check out Apple's AirPort's but they have two versions but I don't know enough about internet and connection speed and so on to know which one I need. Some people say the Express is good to extend the connection strength. While others says it works great as a main router.

Should I go for the Extreme or Express? There are 2 people connected on the internet every day. Me and my brother.
It's an issue of what device you'll be using, how many of them will be connected simultaneously, if you need to stream music, etc. But based on what you said, here are a few suggestions:

In general, if you have a new Mac (mid-2013 or later, for most models), it probably takes advantage of 802.11ac, a spec which only the Extreme supports. However, if you want to stream music via AirPlay to speakers connected to your router (especially if your router is in a room you use a lot), and you're willing to give up some power, the Express might be a better choice. Another thing to note is that the Extreme allows for  both the connection of printers and external hard drives, should you wish to perform wireless file transfer/backup, while the Express only supports printers. If you plan on attaching Ethernet cables to your router, you may want the Extreme as it features four Gigabit Ethernet ports, whereas the Express has only two older-spec 10/100BASE-T ports. If you have a bigger house that needs better coverage, perhaps consider the Extreme.

For further reference, and a very useful comparison table, see Apple's "Compare WiFi Models" Page.