How to fix gears on a Kilimanjaro bike I've just bought a Kilimanjaro bicycle for cheap. One reason it was cheap, I expect, was the gears system. It's only partly functional, and I don't understand why. I would go to the bike shop with it, but they'd charge me five times as much as I've paid for this bike, and I still wouldn't have an idea what to do if this happens again. 

Rear gear minimum position (second-to-smallest ring):


I somehow forgot to take a picture of the maximum position, but it's like two rings up. I'd like it to be able to go to all rings.

Front gear:



It only goes to the lowest and middle ring. I'd like it to go to the highest one too.

Front gear control:



Rear gear control:



Is there anything I can do to fix it?

EDIT:

I've made a video showing the shifters. Does this help identify what's wrong? Do I really need to replace them? 

Video
You need to read about derailleur adjustments. The first thing to do is check that the rear derailleur is not bent. If it is, you need to unbend it.

Once that has been determined, you can read up on rear derailleur adjustments and front derailleur adjustments. I'm including cable tension as a derailleur adjustment. 

Other problems may be cable friction (replace the cables) or the shifter pawls not catching (replace the shifters). But start with the derailleurs.