I think i would maybe ask around a lil bit. Meaning other photographers get some prices in mind. One thing make it clear to them your not hookin up friends this is a business,make sure you print out a agreement form/contract. Be Professional. I think all day for engagement shoot is a bit much.But my photographer is charging me for 2hrs $150.00 but alot of other things are included such as classic & environmental portraiture,online proofs and digital file for newspaper use. I hope this helps.
Good luck