XPS 15 OS Installation

Hi Guys

When i got the XPS 15 i downgraded the OS to windows 7 and only used 750gig drive to house everything. Now i want to upgrade to original windows 8 OS with it installed on the internal 32gig SSD, which i can do, but when i go to update the Windows 8 OS to Win 8.1 i have an issue that there isn't enough space on my 32gig SSD.

Also, how do you point the default installation folders to the other 750gig HDD?