Hmmm...$200 you say? That's a lot to work with. Do you live in the U.S. (Newegg)? Do you live near a Microcenter (check their website for store locations)?
One idea to start with:
$125 i3-2100
$29 PNY 4GB (2x2GB) DDR3:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820178265
$115 Gigabyte mATX Z68 w/ Virtu Motherboard:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813128495
TOTAL: $269
Z68 allows the use of Quicksync with a discrete graphics card. Quicksync is amazing for video encoding and will cut encoding time in half or better (
http://www.tomshardware.com/reviews/sandy-bridge-core-i7-2600k-core-i5-2500k,2833-5.html ). The slow time shown is probably what you're currently at. The quick time with Intel HD 3000 is with Quicksync.
A discrete card is a must for gaming and cannot be used with Quicksync with chipsets other than Z68 (H61, H67, P67). That's a bit more than you were planning to spend, I know, but if you're doing video work the benefit is earth shattering.
You could get significantly more performance if you got an i5-2500K and overclocked it--but that puts this project another $86 more expensive (i5-2500K can be found for $211 w/shipping on Amazon).
8GB of RAM and a faster hard drive would also improve video editing and encoding performance.
FYI: If you add a graphics card to a Dell, you usually need to replace the power supply to something more reliable.
As you can see from the benchmark I linked above, performance improvements for $269 are huge! You can save $30 and go with H61 instead of Z68 (w/ Virtu), but you will not be able to use a graphics card and Quicksync simultaneously.
I highly recommend that you do not upgrade your current system but instead look into saving money until you can afford a solid upgrade. Why spend $130 for a CPU when double that gets you triple the performance?
An i3-2100 tops the Q9400 specifically in gaming and using Quicksync for video work. In many other cases it loses--but those cases aren't our concern.