Travel from Lisbon(Portugal) to Sevilla in Spain?

[Shaveen]

Hi,

I need to travel from Lisbon to Sevilla on 18th November. I am unable to find any direct trains. The car rental companies are saying they would charge a hefty amount (in order of 800 euros) if I pick up a car in portugal and drop off in spain. Someone also told me that there is some bus which goes but it is very slow and painful and takes 9-10 hours for the small distance.

Can you someone suggest what should i do? In worst case scenario, where do i get the bus from and do i need to book in advance? Any timetable and charges will also be really appreciated.
Plane journey is going to be very costly I believe. We are a group of 4.