Mr. Felix.
As suggested you do need to change your workflow. Leaving pictures on the card until it is full will eventually bring you heartache when it comes to that day when you want to take a few more images, but can't because the card is full. Then by the time you delete a couple to make room, that special moment is gone. I have a friend like that, and she can never find the image she wants to show me. Very frustrating....
I take the files of the card after every shoot. I don't even take the card out of the camera. I use the USB cord supplied, create a folder "
Location-Date" ie; "Bondi 30-9-12" or "Home-Dog 30-9-12" and then load the files into that.
I'm not as good a photographer as the guys above, and I'm just a hobby guy like yourself. And when it comes to find that image that you took a few months ago, all I have to do is remember where, what and when.