Tianjin to Beijing

We are arriving in TJ on Celebrity Millennium ,on April 21 2014.We are 4 people,all pensioners,but perfectly able to get around.We have already reserved rooms in Beijing for two nights(mon and tues).Having listened to many peoples experience,we thought the best thing to do is,get a taxi from the port to TJ Station,from there we could take the bullet train.When we get to Beijing,we will book in to our hotel and spend the rest of the day sightseeing,in the evening,go out for a meal.On the second day we want to book a taxi to take us to great Wall(mutiyanyu)and maybe summer palace.
So how do we get a taxi from the port to railway station,do we book,or just pick one up.Then should we book our tickets on bullet train,if so,how.then can we book a reasonable price taxi to take us to the great Wall and summer palace,also any idea in British pounds,what these taxis will cost.Thanks for any advice.