My S3mini keeps restarting itself

[gmcwlg]

I can't keep my phone powered on long enough to transfer my photos/calendar etc off the phone.
My phone is still under warranty, but if I send it to be looked at they will restore to factory settings and I lose everything on my phone. Any ideas how to transfer data off my phone?
I have tried putting sim in another phone, but apart from my contacts, the data isn't saved to my sim...