Fixing the port yourself is a big complicated. So unless you are very familiar with doing similar work, I would not recommend it. It would be better to take it to someone who has the knowledge and skills needed to do the repair/replacement. But I would call around and get pricing first. If it is close to the cost of a new version of the phone, you might be better served just getting a replacement.
As far as selling it, if it is damaged, it is highly unlikely you would get much if any money for it. However, it doesn't hurt to try.