The problems you have identified do not necessarily mean that your shocks are blown. It sounds more like a braking issue rather than a suspension one.
When you go over a bump...do you hear a squeak from the rear? if you hear a squeak....its the lower control bushing that is seized. New control arms should cost you around 8K to 9K at most.
Honda Civic shocks can go for as long as 300,000KMs (unless you have lowered your car on springs..in that case the shock will blow prematurely)
You dont need a dual core radiator...it is an option. It saves space in the engine compartment but does not necessarily improve performance at all times. It is fatter but it is less wider than the stock. But if there isnt a big difference in price..get the dual core one.
And which bearing you are talking about? How man yKMs on your car?