I am sure you want to upgrade the RAM on your machine from 4GB to 8GB.I had a similar case for my early 2011 MBP (I've not still not upgraded RAM on my machine).
Upgrade from 4GB to 8GB RAM
- How to find the current installed memory and it's details
- Navigate here to match exact details
You can match the exact RAM details that you want for upgrade and that is 204-Pin , 1333 MHz DDR3 RAM.
You can search for same specifics online or in nearby stores.
Using 1600 MHz in Place of 1333 MHz
This question has previously been answered on this forum itself and I take no credit in providing the link
- Can I run 1600 MHz instead of 1333 Mhz?
- Using 1600 MHz RAM
Using 16GB RAM in your MBP
As discussed here, you can use 16 GB of RAM in your MBP. (Please leave a comment if you successfully do this as I will also be interested in that.)
Let us know if you successfully choose any one of these options or we can count on someone who has already done it and would like to answer this question.
Good Luck !!!