Can I extend after marrying a German National?

No it does not. In fact, if you had longer in the Army you would be sent back to the states without your foreign national spouse.

You can extend, or at least may be able to extend, if you have not been placed on assignment. OCONUS stabilizations have to be sent to your MACOM, in this case USAEUR, to determine the strengths of the MOS in your location. So, you might be able to extend your DEROS six months by extending your ETS a year. Or you could reenlist for 2 or 3 years and extend your DEROS 9 or 18 months, respectively, giving you enough time to get a green card and gain command sponsorship for your spouse.

Being married to a foreign national does not change how the Army assigns you. In fact, it will make investigations much longer.

- housing: just as eligible as anyone else that has dependents
- Foriegn Service Tour Extension: nothing special about marrying a local national. You would need to extend your enlistment to do an extension request. If you meet the time requirement To PCS, you can just as easily PCS.
- Go talk to the reenlistment NCO to see what options there are.