KLIA ekspress is 35 MYR per person and takes 30 min to Sentral. From Sentral to Hyatt is about 15 depending on the size of car (economy, red taxi was 13 for us last month). At Sentral, you buy a prepaid voucher for a taxi (hotels also provide taxis that use meters, so no need to haggle). From Sentral it should be around 15 min to the Grand Hyatt

From KLIA taxi is about 70-75 but it should take an hour at least.