SSD and RAM are two different things.
SSD - Solid State Drive. It is like a super fast hard disk in which you can put in your OS and other important and heavy programs for them to load faster due to high data reading capacity and bandwidth.
RAM - Random Access Memory. It is able to catch whatever you do or view for speedier loading times the next time you do the same. Yes a higher RAM would make your PC more smoother and faster to some extent and the difference would be noticeable.
You should go for another 2 GB or 4 GB stick. That would total for either 4 GB or 6 GB RAM.
These days 8 GB is standard but 6 GB is also a lot.