I hope this helps to understand the scope of the promplem and ocean curent dynamics at work.

There are 2 gyres, the "Eastern Garbage Patch" off the coast of California (the larger) and the "Western Garbage Patch" off the cost of Japan/Philippines.

This is an enhanced photo of the Western Patch which sppears as a whitish vortex at the center.

Next is a lowres screen cap of an animation illustration the system followed by a link to an excellent animation and the source article.

gyre vortex animation (FlashPlayer required)

Altered Oceans  LA Times Online (FlashPlayer required)

I've got some other photos in my online archive but seems I can't access now so I'll try later. These are arial survey photos can see the plastic islands.

I hope you can understand the scale of the problem from thi.