I need to remove the oil pan.Do i have to remove engine?

What engine?

i know the four cylinder, you do need to lift the motor just a few inches.

I'm sorry. Yes the 2.5 What do you mean by raise the engine a little?

Short Answer, NO

Long answer keep reading
Haven't done a 4cyl but did a 6 and should be about the same.
I raised the car up on jack stands. put a screw jack under oil pan with short 2X4 between them to not crush or scratch the oil pan. Sat a short 4x4 on each shock tower and a longer 4X4 across them across the engine bay. Un hooked front motor mount raised motor up with screw jack about 4 inches and chained motor to 4X4 removed front motor mount and screw jack pushed exhaust over using another screw jackand removed oil pan.
Thats how my story goes and Iam sticking to it
Good Luck

I did a similiar thing for the v6.
I undid the pass side lower motor mount.
by the back of the car, by the oil pan there was a lip which I could put a 1 inch wooden dowel on and then used a floor jack to raise the motor via this dowel(broom handle).
I could then remove the oil pan. (ITS A BIG PAIN!!!)

I love then Pontiac manual.
1) remove oil pan bolts
2) remove oil pan

I could only hope!

I bought an engine hoist,

First you have to remove the aircleaner
remove the bracket holding the alternator, remove the alternator, raise the vehicle, remove the flywheel protector, remove the starter, remove the engine mount, while the engine is being held up somehow( the use of the engine hoist)then you can remove i think its 16 bolts from the oil pan.

You can also rent an engine hoist, i bought one because i will always use one in the future.