Dear @Shareef,
Welcome back at Wefugees and thank you for reaching out to us again.
We discussed a similar question here before and we emphasized how important it is to apply for the residence permit according to section 25b in good time before your current permit expires. Then, your status automatically continues until the Ausländerbehörde makes a decision on your application and you will have a bit more time to submit the language skills proof. The paper they issue which confirms this continuing status is called a 'Fiktionsbescheinigung'.
The Fiktionsbescheinigung allows you to continue to work. You do not have to apply for an additional work permit or anything else.
With regard to the language test: As far as I have heard so far, the immigration office wants to see an A2 certificate (you must have at least reached level A2 orally). If you don't know where you can take a language course or a language test, it's best to contact a counselling office in your area. I think the tests from Goethe-Institute are quite expensive. Nevertheless, you find a lot of study material online as well (i.e. on YouTube).
I hope this helps and all the best,
Meike