You should absolutely NOT get married within the first 30 days of her entry to the US as a visitor. Doing so will severely jeopardize her ability to adjust status to permanent residence. You should not get married for at least 90 days after her entry to the US. Then you can file for her permanent residence with your local USCIS office and she will be eligible for employment authorization within 90 days of that filing. As far as the timeline for getting permanent residence, this depends on where you will be filing this petition, since processing times vary from one district office to another.
Please let me know if you have any additional questions or need further assistance with this matter.
Admitted to practice in CA, AZ, IN and OH