No one in the anglophone world will care that you don't have an Abitur. The UK's Open University has open admission. If you have the £5,000 for a full time course load for a year they'll let you in.
Assuming three years of vocational school refers to Fachhochschule you would at the least be admitted straight into most computing degree's second or third year. Given your work experience you could probably get into some Master's degrees. Peterep down thread says he got into Oxford's Software Engineering Master's without a Bachelor's degree. His email is in his profile.
I'm not entirely sure on the details, but I hear that Open University degrees are not recognised in Germany for the very fact that there are no entry requirements for bachelor degrees. Of course, this would apply to any university without entry requirements.
I may be wrong about this (and if anyone here can set the matter straight, that would be great), but I would strongly suggest finding out more about recognition if this may pose a problem.
Assuming three years of vocational school refers to Fachhochschule you would at the least be admitted straight into most computing degree's second or third year. Given your work experience you could probably get into some Master's degrees. Peterep down thread says he got into Oxford's Software Engineering Master's without a Bachelor's degree. His email is in his profile.