Unfortunately it has a maximum supply voltage of 16V so it needs a regulator. The sensor you've linked to requires a 6V power supply. An LM317 could be used to power both the sensor and the op-amp.
Do you know the resistance of the relay coil or how much current it needs?
If it's >500Ω or uses less than 50mA the LM311 comparator could be used to drive the relay directly, if not, you need an additional booster transistor.
From what I understand (assume) i will need a 12/24v relay working at 300Ω?
would that make sense?
Forgive me.. I really am a learn as I go person (i try my best to learn as quick as possible as to not annoy anyone to much). Whatever information i will take to my local tech shop and get them to help decipher it for me.