Based on what you have described I would be inclined to suggest you stick with the P&S. You don't seem to have described any true need for a DSLR. The reaons to go with a DSLR would be:
- P&S zoom is too limited
- P&S wideangle is too narrow
- P&S low light performance is too weak
- P&S camera is just too small & light weight
Both of my parents are in their mid 60s, they both have the same Canon P&S (Ixis?) and both are very happy.
My dad uses his to take photos when doing insurance inspections and he doesn't need 16megapixel images of fire hydrants, sprinkler heads etc
, he also takes basic photos when on vacation.
My mother loves the compact size as she can put it in her pocket and take photos at preschool & also of the grand children at home, the P&S is less obvious to the kids so she can get more natural shots as the kids arent all posing. She also enjoys taking it on the holidays so she can get the photos stuff she wants that my father ignores
Complaints? The only one I have heard is that my mother wants a better zoom for the holiday photos (scenic), but knows she does not want to lug around a bag to hold something like a 40D and also knows that the cost of the equipment will not provide her with enough reward.
If you were to go with a DSLR, I would be concerned that in the price range you are working the lenses aren't exactly amazing, other than maybe on the telephoto range you might not find any benefit and although we try keep away from megapixel comparisons the 6.1MP Canon probably isn't all that desirable. Maybe moving up to a Canon 30D in the 8s might be more rewarding as the quality would improve.
Finally, when it comes down to it. Ask yourself one question. If I have a DSLR, am I really going to use it as much as I would a P&S?
You have more weight, bulk, etc to carry around, do you think you will take the DSLR to every event you go to like you would a P&S, sometimes a smaller more subtle camera can get you further as people (subjects) aren't afraid of them like they might be when you whip out the DSLR