Alright, to those who don't know how to get the gold portal or how to beat P-Bot, let me break it down.
You get to the gold portal by changing to Salad Fingers and walking on the invisible pathway to the gold portal.
When fighting P-Bot as Salad Fingers, deflect his missiles using Salad's finger puppet attack; do not confuse this for the freezing attack where Salad waves his arms about. Only use the freezing attack to put distance between you and P-Bot so that you'll be in range for him to fire a missile at you. Be sure to close the gap when he does fire it, however, because the missile will not simply shoot straight back at him and will hit the floor before P-Bot comes anywhere close to it if you're far away enough.