If you fancy visiting a pub near the train station there is the Battle of Trafalgar, just up Guildford road, it's like a 1 minute walk, or the Prince Albert, just down Trafalgar Street (outside the station there's a road that runs under the front of the station, go down there). Both of those should be full of Albion fans. At the stadium itself there is Dicks Bar (named after former chairman Dick Knight) but by the time you arrive I'm not sure how long the queue would be to get in (it's open after the game too). You can also get a drink inside and outside of the stadium.
The TVs in the concourse and Dicks Bar usually show highlights of the game shortly after FT so if Jahanbakhsh has scored the winner you could find a TV to watch it again from every angle. ;)
I'm going to the game but travel with 4 others and it tends to be a case of arrive as late as possible and leave as soon as possible (never before the final whistle of course) and we come from the east so don't go via Brighton itself. If plans change though I'll send you a message!