I am in my sixth week of training for a 10k, my longer run this week is 4.5 miles. All of my miles have been on a treadmill. Once I finished the 8 week training, I'll still have another 5 weeks before the road race. What suggestions does anyone have about how to continue the 10k training for the remaining 5wks? Also, when/how should I transfer to running on the road?
Once you get your long run up to 6 mi/10K distance, you can continue at that maintenance level with your longest weekly run at that distance. That will keep you in good shape for a 10K race. Better yet, once you reach 10K distance, you can progressively increase the length of your long run to 7 or 8 miles over the last several weeks. That will help build your endurance further, and will make the 10K distance seem short by comparison.
As for transitioning from the treadmill to the roads - Start transitioning as soon as possible, if you haven't already. The more experience you have on the "real" race surface, the better, and the more confident you will be on race day.