1. Your best bet as someone already having an undergraduate degree is likely to be either
A. as the other reply said, apply for an accelerated BSN program, get your experience, then apply for your masters separately, or
B. apply to direct entry programs (those for which you're accepted to the BS and MS nursing degree programs together. They are usually somewhere in the 3 year long range. Once you get your BS/BSN (or pass the NCLEX as not all programs will actually award you the BS degree, some may simply give you the MS/MSN when you're done with the entire program but once you finish all the appropriate elements of the program you can sit for the NCLEX) you can start working as a nurse while you complete the rest of the program.
2. The above being said, some masters specialties (particularly the acute care programs) will require you to 'step out' for a year, or do a 'residency' lasting anywhere from several months to a year before you're allowed to continue in the program. With that plus whatever work you do while in the masters you'll likely rack up about 2+ years of RN experience by the time you graduate. This will be enough for some people and not enough for others.... I can't speak specifically about primary care oriented programs, but I do know that you can often do those programs part time (many acute care programs won't allow this) so may be able to rack up even more RN experience prior to graduation.