Transferring from USB 2.0 external HD to USB 3.0 external HD

So what you're saying is that - while I can make adjustments on my computer (re: "this device can perform faster") - I will only be able to transfer data as fast as the slowest device...and an expresscard won't help. This is what I thought. Thank you.
 


If you would humor me: What is the express card I linked in my question FOR? I have read and read different product reviews, but can't seem to figure that out. I appreciate your almost immediate answer of my question, as it shifted my focus in my task of transferring so much data, and - of course - saved me the trouble of buying something I did not need. Thank you!