Try sprinkling some cinnamon underneath the lid. It is believed that this may make the pumpkin last even longer.
Be aware that hollowing out the pumpkin can be very hard work at times - an ice-cream scoop might make this part of the job easier.
Don't throw the scraps away! You can make delicious soups with the pumpkin pulp and dry out the seeds to plant and grow new pumpkins for next Halloween!