NOT A BIG ISSUE.

I advise, it's better if your husband sponsor her. Following documents should be ready with you.

1. You need a letter from your HR (if your husband is going to sponsor ask him to get one from his office for mother-in-law)
2. Copies of your/your husbands (better to keep both) ID, Birth certificates, Marriage Certificates, Passport copies of your mother and you.

Prodcedure:
1. You go to Immigration Office in Gharafa.
2. There are so many typist and you need to get typed the application in arabic by one of them. They will charge you QR 5/-
3. Then you go to counter no 4. Once you get your turn go to the counter and provide your documents. As your mother is above 60, most probably you will need to see the officer in upstairs (2nd floor). The counter staff will put some comments your application and will direct you to the officer.
4. Go there and meet him he will consider you application and sign it.
5. You pay visa fees and within 2-3 days you will get the visa.

Best luck.