well first of all there is no reason that you can't maintain it...I'm sure if you work hard you would be able to. However for what you are asking that is somewhat irrelevant and would be for you to decide.
You can not transfer internally and continue your degree...a transfer is exactly that, you change from one course to another...which certainly isn't the case if you continue the other course...you can't tranfer and apply for a leave of absence for that degree only.
Your options are to either transfer mid semester if you are worried about your GPA...this would mean stopping your other degree. Or you can wait until the end of the year and see how things go. You may have the GPA you need then...if not as cape said you can apply through UAC...perhaps writing a personal statement to support your case.
Though I don't see why you would want to transfer, and still want to continue the course you are doing at the same time. You really will have to choose between them...or choose between these two options according to what is best for you