One thing that will help is to shoot your image in RAW mode. This will preserve the most amount of detail which you can pull back in post. You see once you compress an image such as a JPG, some detail is lost. However with a Raw image you can reclaim quite a bit of detail from the highlights and shadows that wouldn't have been possible in JPG.

Another thing to do is to reflect some light back onto the flowers. This can be as simple as taking a piece of white card and bouncing the light from the window back onto the subject. This will help to add a fill light.

Incorporating RAW and bouncing the light should get you the desired effect.

A CR2 file is a RAW image file. I'm not sure about windows but on mac you can preview these within finder. When you open them in photoshop it should default to opening in Adobe Camera Raw. This is where you can edit your raw images

This can be achieved by slowing down your shutter speed in video mode. A good rule of thumb is to set your shutter speed as double your frame rate. So if your shooting at 25p (PAL) then set the shutter to 1/50. However if you are outside in bright daylight more than likely need an ND Filter to block out some light. Otherwise you'll ending up having to set your aperture to f22. Because if you slow your shutter speed this will allow more light to enter the camera.

But if your shooting at night or inside you should have no issue creating a motion blur.

Not too sure about free sites but I have used sites like:

Premiumbeat.com
Pond5.com
Themusicbed.com

Again, these aren't free sites but if you're working on client based jobs then factoring these into your costs is a good option.

I'm in the market for a new camera but I'm nervous for the same reason. I was looking at getting a C100 but I fear Canon could release something new. Decisions, decisions...