It's always nice to get views from others, but at the end of the day, it's your life that will be changed by your choices.
First off, your contract and situation suck!
Second, your employer and placement agency should be embarrassed. ( If not arrested! ) It sound like if you sign the 2 year contract that your employer has you in a bind for 2 years!
My advice is.... you're young. Get all the experience and portfolio samples you can while working at this place, along with forming a plan on what path you're going to take. Start putting those pieces together TODAY!
Don't wait for things to happen. Plan for them and work to make them happen.
As far as salary goes, it depends on a lot of factors.
Where you work.
What you do. ( Or are expected to do. )
Location.
The need for somebody with your skills.
Etc.
I've worked creating multimedia, etc at a few places. At some I was expected to do everything from creating the images and sounds, to assembly and coding. Blah, Blah, Blah.
At others I was just asked to do the design. Coders put the piece together.
At the Ad Agency I'm at now, it's a whole new ball game. Every piece of the project is handled by a different Dept.
Anyway, the salaries have varied. It seems that the MORE you do, the less you get paid. That's probably because if you're doing EVERYTHING, you're probably working for a small company. Hence the low salary.
I won't tell you the salaries I've made, but I can tell you, work toward bettering your skill set, and one day you will be paid what you feel you're worth.

Peter