I have the same Mac but don't have those issues. When researching it before buying though I see that a number of people complain about wifi drops from both bluetooth usage and USB 3.0 drives. As a troubleshooting step you might try removing any external drives and disabling bluetooth to see if that clears up.
Even before that though you might want to do a few things: -
- delete and add your wifi connection
- delete and add your wifi adapter from network preferences
- try other wifi access points to see if the problem is universal
- enable 5ghz on your wifi if possible. The issues with Bluetooth and USB drives I mentioned above are due to interference on the 2.4ghz range