You don't sound ready to move on. As you said with Chris, you'll be likely to get hurt. Never go into a relationship with a man thinking you'll be the one to change them. It never works. Wait until you meet someone you don't want to change. And if you're not attracted to Joe, you can't force it, no matter how nice he is. You'll just make yourself unhappy.
Do other things. Go shopping with your friends, spend time with your family, go for walks, read books. Just fill your life with other things. There are much worse things than being single, especially when you're young, and top of the list is being in a relationship with the wrong person.
After splitting up with my first (and so far, most serious) boyfriend, I was single for two years. At first it was really hard, but by the time I met my second boyfriend (the mistake!) I was so busy having a nice time being single that I was in two minds about whether I actually wanted a relationship at all. When I got together with my current boyfriend I'd been single for less than two months and was still pretty upset about it all. One day I was still crying over the breakup, the next day I was talking to this guy and thinking, "You're actually really attractive... why didn't I see this before?" and that was that!
The one solid piece of advice I can give you is that you'll know when you're ready to move on. You can't hurry up the healing process, but you can definitely make it easier by spending more time having fun with your friends. As soon as the next person comes along, you'll immediately know you want to be with him.