Have job offer.. what is a reasonable pay for Germany?

I feel fortunate to have a job offer at an IB school in Germany. I am a qualified teacher with 9 years teaching experience and alot of it overseas, and now I have a job offering with a few last minute conditions to be looked at, but the offer is 2500 euros a month. My question is : how is this for a professional pay in Germany? I make more here in Canada and have to give up a job for this, but want to be there with my girlfriend and I think it is alot more difficult for her to find work here.
So it seems good, but how about taxes and then I guess I still have to pay Cdn. taxes too. But how is the cost of living there since I figured it is about $3500 cdn. a month which can work here, but not sure what deductions to expect.. that is a net pay not gross that they are offering.. so before deductions.. I have yet to talk to them to ask questions so I am just putting it out there for some feedback.

thanks in advance.

2500 Euro is not much money for a teacher in germany.

e.g.: In Berlin 3400 Euro brutto . Netto 2000 Euro. This is the payment for a german teacher, the netto exclusiv the tax and the insurance.

The rent in Berlin in for 43m² is 390Euro. In Cologne it is 430 Euro. That include the cost: water and heating energy.

If I were you, I would try to get a deal: 2800 Euro for start and after one year a bonus 200 Euro.

Yeah, I've found out that you get taxed so much living in Germany. For a qualified teacher, 2500 doesn't seem like much after you get taxed but I don't work as a teacher so I'm afraid I'm not sure if that is normal. the cost of living is really cheap over here though. good luck!

As angemon84 already posted, the monthly rent differs between the german cities. Berlin is actually quite cheap as you can see here for example.