Do you know what class your memory card is? I have a Class 10 Sandisk 32gb that I use for my GoPro, but it'll struggle to record 720p at 60fps for a prolonged amount of time. it'll usually record for about fifteen minutes before it stops and I have to hit the record button again. It copes fine with 1080p24 or 720p30 though (due to lower framerate).
As a general rule, cards with less storage (like an 8gb or 16gb) have a better transfer rate (like 45mb/s+) and can handle the large amounts of data being stored to it.
You can buy a class 4 32gb sd card and, although it has more memory, its not suitable for a video recorder due to the low file transfer rate (like 4mb/s or something). This would be fine for something like a digital camera, but for a full HD video recorder simply wont work. Try turning down some of the settings on the camera if you can, and see if that works. If its set to record at 60fps it'll really struggle, so turn it down to 24fps (which is standard really. 60fps is only really useful if you're doing slo-mo stuff), or if recording at 1080p reduce it to 720p and see how the memory card copes.
I'd recommend buying a new memory card, but keep an eye on what class and transfer rate its got. Just my opinion (and I have a degree in Media Arts
)
Let me know what you decide to do, and if you want a new sd card I'll have a look online when i get home and recommend some for you.