Help plz

Hello,
I have a hp pavilion DV6707us and am looking to upgrade the ram i know it can handle up to 4gb but i don't know what the max speed it can take is.
Right now it has the stock 2gb of 5300 and i also just got this and payed $557USD do you think this is a good deal because i still have 10 days to take it back if i like.
thanks in advance for all your expert opinions.

 

It can handle DDR2 PC2-6400 or DDR2 PC2-5300
You can get a good price on RAM here:
http://www.crucial.com/store/mpartspecs.aspx?mtbpoid=7AD47362A5CA7304
Please note: How much memory your Windows OS will recognize depends on which version of Windows you are running. 32-bit versions of Windows will see (and utilize) only 3GB or 3.5GB. To utilize more memory, you will need a 64-bit version of Windows.

 

And yes, that is a good price for this laptop.
Most places online are asking $700 to $800 for it.

 

Ok thx alot.
I Have Vista 32bit,
now since i will be putting in 2x2gb sticks and losing .5 to 1 gb due to vista will it still run in dual channel?