... I don't think you understand what switching to architecture means. You'll likely start from zero if you're switching to an accredited architecture degree and that stellar 2.9 GPA will be stressed given the increased difficulty of the discipline.

If this is something you are seriously considering then I would work on increasing your GPA and begin working on personal projects to create a portfolio. Apply to a 3 - 3.5 year Masters with your degree.

I did it (and my GPA was about there sophomore year, got it up above 3.2 by the time I graduated).  Took photography and drawing classes on the side, used what I learned to study spaces and create images for a portfolio.

if you are seriously with architecture, go with 3.5 year master programs. takes more time and costs more money. but if you really want architecture, it is probably the best way. most of people follow this path hold non-architecture undergraduate degrees. are you still going to school now? if yes, take some beginning and fresh architecture courses at your school if they allow you to do so. those courses will give your more sense and orientation about architecture than other photography and drawing classes. don't get me wrong. photography and drawing are great and help a lot in architecture, but architecture classes will bring you closer and provide more insights to the profession. i have witnessed many people dropped out just because they had pictured architecture way too romantic. studios and reality are harsh. however, many without architecture experience before are absolutely great. good luck!