I've not done what you are trying to do before so proceed with caution. One method may be to use MacFuse if indeed the partitions were created by a Linux distro (flavor). However, if you formatted the drive on a PC using Windows then it is a possibility that the drive is formatted as NTFS and in that case you would need to try something different. To err on the side of caution I won't recommend a possible method until I know for sure what file system the drive is using. Could you post a screen shot of what you see in disk utility.
To take a screen shot do one of the following:
Full Screen Shot
Press Command + Shift + 3.
Screen Shot of a Portion of your screen.
Press Command + Shift + 4.