Also note that once the maximum number of Bitcoins are created (~21 million) fees will become more important to the network as the miner will no longer receive new Bitcoins as a reward.
Is it possible to increase the amount of bitcoins?
No, there is no way to increase the number of Bitcoins above 21 million. However as deflation occurs due to a lack of Bitcoin production we could deal in millibitcoins (1/1000 of a bitcoin) or microbitcoins (1/1,000,000 of a bitcoin).