Buy this at the Toyota dealer or you can buy it at Ebay, check Item number: 260285348932. Just pry the old one out with a screwdriver and insert the new one. The only one left on your fuel door is the plastic, the V shape metal is missing.
To temporarily open the fuel door. Lift the gas handle inside, and wedge something underneath the gas handle to keep it up. Now, go to the fuel filler door and stick a credit card in the gap and pry out the fuel door to open it