There is another option.
1st of all back everything up with something like clonezilla just in case something goes wrong.
I have successfully converted a primary partition to extended. I had a friends laptop with the same layout. I followed this guidehttp://www.partitionwizard.com/convertp ... ition.html
Afterwards, I was able to create new partitions and install mint. I also tested out the windows recovery and it still seemed to work. I didn't go through a recovery, but did boot into the recovery program.
Please back up first though. Messing around with partitions can really mess things up (for current partitions that is).