what is the cost to have this repaired and can someone explain wat sort of damage this is and how it is caused?

The dipstick thing is an effect & not the cause.

The cause of ur problem is cylinder bore or piston ring damage.

Poor cylinder bore sealing results in what is known as blow-by.
This is what happens when the rings cannot seal properly against the bore , resulting in air/fuel that should be compressed slipping past , or blowing by the piston back into the crank case area.

In some cases it can blow the dipstick out of its holder tube, spraying the engine bay with oil.

You likely would also find that u have a substantial amount of oil residue in the air cleaner box.

Rings should last about 200,000 kms , or more depending upon oil & air filter service intervals & driving styles.

l see Brava is here with 350,000kms on the first engine & still going good.

Unless ur car has gone further than these ,then likely it has had a partial seizure (from overheating)

Your best bet is buying a complete exchange reconditioned engine, & be prepared for a substantial bill.

Thats what happens when u drive cars with no water.