Can I switch over to full time Guard in the middle of my part time contract? If so how do I go about doing this?

Take it from one who was a former AGR in the MSARNG, you will not be doing much MP work. As an AGR, you will be pushing mountains of paperwork. Much of that paperwork will be a duplicate of the paperwork on a federal level since you work for the National Guard. My advice to you would be go active duty.

I would agree with SSG Hartwigh, for the Active Guard and Reserve (AGR) route, start with the Guard recruiter. They can probably tell you what forms you will need and where to look for the solicitations. In the Army Reserve, AGR job solicitations come down through one of the human resource systems, so I would suggest talking to your S1 if the recruiters aren't helpful. Getting hired as an AGR is a lot like getting hired at a civilian job. You have to meet the requirements, sit for an interview, and then be selected over the other applicants. Most AGR positions are SGT and up but some times a SPC can hold an NCO Positions. If you get the job you will not necessarily have to pay back any enlistment bonus you may have received. It will depend on the wording of your individual enlistment contract.

Alternatively, usajobs.com should be your next stop. I see full-time MP jobs on there consistently. I can't tell you much more about how the hiring for these jobs actually work. The National Guard has some very strange hiring practices due to its state and federal nature. Some jobs are just like regular Army jobs but are considered civilians in uniform. You will also notice that many of these listings require you to be a member of the Guard.

Lastly, you can check Tour of Duty or ask your S1 about doing an Active Duty for Operational Support (ADOS) Tour. These are temporary full-time assignments, usually 6 months to 1 year in length.

Well you have a few options.

First would be apply for AGR for the NG, the second would be way harder since you are a new soldier on contract your state will probably not want to release you but you could see an active duty recruiter and fill out a DA368 and send it up your chain of command which has to be signed by your first General officer in your COC (If you have any bonus ect you would be responsible to pay that back), and the third would be go up your COC and see if any ADOS orders are available. Also you could try and login to Tour of Duty and see if they have any open positions you can apply for which it seems like they always already have someone selected for that and they just have to post it.