After you buy the new ornament, to take the old one out, get a small Phillips head screwdriver and a big, soft rag. Basically, you just use the rag to keep from scratching the paint on the hood as you work the screwdriver (may be easier with two) underneath the ornament, and slowly work it up enough that it just pops right out.
The ornament has two posts at the 3 and 9 o'clock position. Work evenly at these two points. An alternative to the screwdriver and rag are silicon tools that won't scratch the paint. These can be purchased on BavAuto.com
A PHILLIPS SCREWDRIVER?