Upgrading hard drives on a Dell Inspiron 9300

I’m looking to upgrade my hard drive on my Dell Inspiron 9300. There is some kind of extender on the installed drive, right? Does this affect the kind of drive I can install? My current drive is 60GB, and I’d like to upgrade to at least 160GB. Does anyone have any suggestions for a good brand?

You’ll have to bear with me — I’m not very familiar with tinkering around with laptops!

Thanks!