I am not sure but I think the decrease in the price of the bitcoin is only ly due to the DASH and the ETH
No.
It's actually the other way around: Dash and Eth are rising because of the insecurities related to the Bitcoin hard fork. They're used as a "hedge". In ancient times (2013) LTC used to be that "hedge token", now it's ETH and Dash, although I am pretty sure that Dash has already seen its high.
Is there any possibility of increasing bitcoin price?
In the very short term, $1000 must be crossed again and the sharp downtrend of the last weeks would have been broken. In Bitcoinwisdom, the critical point at this very moment is exactly $999

In the mid- to long-term, all depends on how does the Bitcoin community resolve the "scalability debate". Actually the fork risk is a little bit lower again and Segwit adoption is rising, so I'm a bit more optimistic than three days ago.