Noooooo Sally ... don't do it. Having had a bridge camera, within six months I got disillusioned with it - the smaller sensor makes images nosier and they're just not quick enough between pressing the button and taking the picture.
If you want to try macro work... for a lot less money than a macro lens - try either a close up lens/filter or extension tubes.
Getting serious wide angle is more difficult on a budget ... but a bridge camera wont give you that either
Stick with your D40 (my first SLR was a match needle fully manual with a 50mm standard lens no zoom) you've got loooods more versatility than that
