You can apply for the work permit for qualified employees with your German university degree and a proper job offer (§18 Abs. 4 AufenthG).
There is no salary limit for the work permit with § 18 AufenthG, but you have to be payed equal to other employees in your field of work.
Documents required to apply for the work permit corresponding to your qualification:
- passport (+residence permit, + green paper)
- application form („Antrag auf Erteilung eines Aufenthaltstitels“)
- one recent biometric passport photo (not older than six months)
- graduation certificate
- contract of employment
- job description frorm completed by the employer
- proof of health insurance
- 100 euros (you can pay with debit card/ec-card only)