1| Mind sharing the make and model of your motherboard?
2| Have you made sure your motherboard BIOS and chipset drivers are all up to date?
3| Yes you will benefit from adding ram but please do note, that when dealing with ram upgrades it's always best practice to not mix and match ram kits and go for the highest possible ram kit your motherboard will support. Note that I mentioned the need for a ram kit since they will be matched out of the factory off an assembly line.
4| One other thing to ask is to state the make and model of your existing ram kit/module. The spec's to it could tell if the frequency is what's holding you back.