How to save video attachements from an e-mail on Iphone 4s? IOS 7?

I've been trying for 4 days to get a video from my PC to my iphone 4s camera roll, and nothing is working! I saved the videos as 'movies' into my iTunes and it synced successfully, but it doesn't show up into my camera roll. So the last thing I resorted too was e-mailing the video to myself and trying to save the attachment to my phone, but it won't even let me do this! Does anyone have any suggestions or anything? It doesn't have to be just how to save an attachment in gmail, but just any way whatsoever to get the video from my PC to my camera roll. This is so frustrating.

You can't do it from your pc to iPhone.
you can however do it from your mac to iPhone:

IOS generally only works on PC.

Go on to email on phone
Then download and save