Good job.
Exposure comp is just bumping the F stop up or down. Same thing as I described above with the white garage door.
You do not need to shoot in RAW. I shoot RAW images only when photographing latent fingerprints under a light source. Lots of agencies (police) used to shoot in RAW + reg format for all pictures but they are slowly moving away from this.
A digital SLR will have more functions than the basic point and shoot. Some are very reasonably priced.