differential op amp - never done this b4

Hi

i am a total numpty for this, but do know which end of  a soldring iron to hold and how to take basic multimeter readings

i have a sensor output of 2.5 to 3.5 V DC

needs to be 0.5 to 4.5 V DC for a low current digital gauge

so i need to subtract 2.0 V from the input

and then multiply this by 4

as far as i understand i need a differential op amp for this, i have 5V to power this, or 13.0V from a battery / alternator

now i am stuck, how do i work out what parts i need and how to design the circuit ?

many tnx :)