editing the /etc/fstab file is the right way to go. kudos to you for finding that! it's a protected system file, so you need to use sudo to edit it. how are you opening it right now? here are some examples (all from the command line):
sudo pico /etc/fstab
sudo nano /etc/fstab
sudo vim /etc/fstab
sudo emacs /etc/fstab
personally I use vim, but a lot of people find pico or nano easier to get the hang of.
once you have the file open and can make changes, you need to find the line(s) that refer to the filesystem you want to change. usually the format is:
device mount type options
you need to add "users" to the options. for example, here is a windows fileshare that I mount automatically when my computer boots:
//10.0.1.146/c$ /mnt/windows cifs credentials=/home/mcd/.cifscreds,users 0 0
don't worry about most of that, but the "users" at the end is what gives my user account permission to add, remove, and change files. post up if you run into more trouble.