I concur with my brethren. You have that ideal mix of "cute" and "hot" - hot enough to stop any man in his tracks with just a look, but cute enough to take home to meet the parents. That you look as beautiful as you do in low-res webcam shots is a testament to the beauty you have above - not just below - the neck.
Which brings me back to your original question. I, for one, see no reason why you would need to go bigger - you're outstanding as you are now. But, the choice is ultimately yours, and you have to do what you, and only you, think is best.
p.s. with the purple bikini, did anyone else think there was a resemblance to Aki Ross, from the cover of Maxim's Hot 100? obviously, Marie has the far bigger - and better - chest, but that image came to mind as soon as I saw Marie's webcam shots