No one can help. This is problem with Some Macbook Pro, iMac's and Mac Mini's but not all.
It is reported all over the Net with no real solution.
Some of the links Linc posted may work or they may not.
It just seems very odd that all other devices connect and stay connected to many different wireless routers but certain Mac computers can not connect or stay connected for any length of time.
I suggest you Throw it through a Window. Preferably the Window of the store you bought it and the place that told you it was your router. If they are one in the same.
In addition to the links indicated by Linc Davis, there are several long-running threads on this topic, eg
If you have the stamina, you can through them and see if any of the many solutions suggested work for you.