Dell inspiron 530 video upgrade

HD 4670, 4650.

you can get a 4670 or grab a cheap molex adapter and run the 9600GT, 9800GT, 4770 or 4830

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

The PSU is only 305W if I'm not mistaken.

I recommend this one I have it myself and it is amazing:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

If a dual slot card won't fit in your case then this one is the next best one:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

OP just to let you know...if you plan on gaming above 1280x1024 than any of these cards will be very underpowered..

Rewindlabs is right, if you're gonna go any higher than that or want some futureproofing then a Radeon HD 4830 or 4850 would be more suitable. I would suggest the 4770 but HIS hasn't produced one with an IceQ cooler yet  

HIS IceQ Radeon HD 4830 Turbo: http://www.newegg.com/Product/Product.aspx?Item=N82E168...

HIS IceQ Radeon HD 4850 Turbo: http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Its for sure the 530 and not the 530s (slimine) right?

it is the 530 and the psu is 300w.
my monitor is a samsung 2253lw if that helps.
thanks to all for the knowledge

You are going to want to go with ATLEAST a 4850 since your resolution is so high....most likely it will require a power supply upgrade...

Or the GTS 250 is another option...it is equal to the 4850...

You may not want to change the psu but to get anything in there that will allow you to play at your default resolution with the settings not all on medium than the 4850 or gts 250 are your best bets...you will also want to overclock them to push that extra performance out of em

What will you be using the card for?

I would hope this is for gaming...most will list if its an htpc....

i will be using to watch dvd's and streaming netflix

In that case the 4670 would probably be sufficient.
I don't think you would need anything stronger since you're not using it for gaming.
But you might actually want something weaker like a 4650 or 4550.