Erick -
Surface RT will recognize 32GB SD card (or larger). Now, you need to delete the existing 16GB partition and start over. Right-Click on Start Menu/Computer Management/Storage/Disk Management. Select the SD card disk and delete the existing 16GB partition. Now, create a new 32GB partition and format it: either NTFS or exFAT (I prefer exFAT). That should work. If you encounter a problem, let me know and I will try to replicate it on my RT.
Good luck,
Russ