Where do I get this certain type of effect for my camera?

I have a Nikon D5000 with a 18mm lens and a 200. I'm wondering where I can get this exact effect for my photos:
http://severedlegface.tumblr.com/post/3032815559/big-love
Do I need to buy a filter? Iphoto? Any help is much appreciated.

What effect?

The blurred background (but in-focus subject)? That's down to the lens.

Appearance of like washed out light but with deep colours and that? That's exposure control (the camera) and post processing (use The Gimp if digital (for all your digital editing needs.

The color effect you are asking about simulates cross processing. You need a photo editing program. Here are some instructions, but there are many variations.http://www.tutorials-expert.com/tutorial/9881/Photoshop-Cross-Processing-Effect.html

or you can try Picnik under "effects" there's a cross processing effect for free.

That has just been tweaked a bit in a manipulation program such as Photoshop.