Should I hire a lawyer now or do i have to do some other thing?please let me know ,thanks
Hiring a lawyer now won't help - you either get a lawyer at the beginning before you submit the application, or after a rejection when you want to appeal. They can't help you while you are waiting.
Order your CAIPS notes, as others have suggested. The notes might say what the delay is from.
The sponsor could also try contacting her MP. Sometimes they are helpful - if they can't speed up processing, they can sometimes at least find out what the problem is. Some MPs don't know what to do, or won't help, so it just depends on what area the sponsor lives in if contacting the MP will be useful or not.