Good
Here's a link to NewEgg, hopefully right to the DVD section
http://www.newegg.com/Store/SubCategory.aspx?SubCategory=420&name=External-CD-DVD-Drives
Several things to consider :
Do you need a burner ? Most are though, I have never burned a DVD, even CDs only a few.
I assume you want this for portable use, so look for a slim version.
Consider the one's listed with "No external power". I think there were 2 ASUS one was not a writer.
They are powered through the USB port, this means one less power brick to carry, and it can be used completly portable (although it will drain the laptop battery quicker).
You can look at Tiger, even BestBuy to.
Maybe run though Bestbuy just to get a look at the different styles etc, even if it's not the same model the concepts will be similiar.
Does this get you going in the right direction ??
If you don't have one consider an external hard drive for backup and extra storage.
You can backup the laptop to it just in case.
PS if you have any other questions feel free to ask, include the model number of your laptop just in case too.
Thanks