Thank you for reaching out to the Wefugee community!
In general, you apply for a working visa from your country of origin at the German embassy (not if you are already in Germany).
But depending on your situation, you might be able to apply for a residence permit. As you are working and if you fulfill certain requirements, the residence permit according to §25b AufenthG ("residence permit for sustainable integration") could be interesting for you. You can check out Isa's answer in the following thread: https://www.wefugees.de/803329/asylum-rejected-just-finished-training-get-residence-permit?show=803376#a803376.
However, if you applied for a Asylum in 2013 and you are holding an "Aufenthaltsgestattung" or Duldung since then, you still may have to wait for another two years (as one requirement is to be in Germany since 8 years).
Another option could be the so-called "Ausbildungsduldung". Please check this thread for further information (it is in German) https://www.wefugees.de/804871/bleiberecht-mit-ausbildungsduldung?show=804871#q804871.
As every case is very different and there are so many factors might being relevant, I can recommend you to seek for individual legal advice, i.e. in a counselling centre. If you need some support in finding one in your area, feel free to get back to us.
I hope this will be useful for you.
All the best,