Who gets my transaction fee ? The miner/mining pool who included my transaction in a block he/she/they mined ?
Yup
Does not the miner gets 25 BTC again for finding each block or these transaction fees actually sum up to that 25 BTC ?
The fees are separate from the the 25 BTC block reward.
The block reward is actually a subsidy to incentivize miners to mine in the early days of the network, as well as being a structured, predictable source of "new money".