SSD+El Cap Upgrade on MBP Intel Core2 Duo?

Hi,

My partner has a really slow 13" Mid 2010 Build MBP running Yosemite.

Her Processor is a 2.4GHz Intel Core 2 Duo

Running 4GB of RAM

I am just about to take the plunge and order the Crucial BX100 SSD HD with 250GB capacity and install this as the new boot drive, whilst doing a fresh install of the OS and only reinstalling essential apps to the main boot drive. She will then run all her files from the original HD, with the exception of any PSDs / TIFs etc that she is working on there and then that will benefit from being worked on from the SSD.

I have promised her that this will transform her system. As a designer she is using Photoshop, InDesign and Illustrator daily and they run drastically slowly. It is beyond the joke and really it is costing her huge amounts in time and starting to delay paid work.

Whilst I understand that there is room for an additional 4GB of RAM with this machine, given a small budget, which is the best route SSD or RAM? And will the system run much faster?

Thank you.