I had a bike with a dent about like yours. Read up on it and sounded like it wasn't a threat. I still didn't want to worry about it, so got another bike. If it bothers you then get a frame and transfer parts or just get another bike. If you read up on it in forums you'll see that kind of dent is not a threat. Its your choice and you have to live with that. If you do keep the bike, sounds like a new set of forks in is order.