By 8mm, I assume that you do mean film. If so, you will first need to have it telecined - converted to digital. If you do this, I urge you to NOT go with an 8mm to DVD-Video workflow. Instead, telecined to tape, or a DVD-Data, would be far better. And yes, PrE will allow you to improve much in that film.
And, of course, it depends on what you want to improve!
As Hunt says, having your movie professionally telecined you'll get much better results than if you try to do it yourself.
But if by improving it you mean fixing faded color or sharpening the picture -- yes, you can do some of that in Premiere Elements. Just don't expect miracles. You can only do so much with this old and not terribly high quality format.