Here are your options:
1. Marry while you are here, and apply for adjustment of status. You would not be able to leave the US (without abandoning the adjustment) for 3 to 6 months. You cannot work for 3 to 6 months.
2. Marry while you are here, then return to home country. Your US souse will start the CR-1 process by filing an I-130. You can visit during the process. Then, in about 18 months, you will receive a CR-1 spousal visa.