Please describe how your internet connection isn't working maximally now. If it's slow, intermittent, etc. then please describe exactly what's happening.
Since an internet connection usually involves an access point, router, cable modem, or other device, any sub-optimal performance may be the result of that device (or devices, depending on your configuration). You'd need to tell us what device(s) you're connecting with, how your Mac connects to it (ethernet, wifi, etc.), and if wifi is used, how close your Mac is to the internet device.
Finally, your ISP plays a substantial part in the quality of your internet. Sub-optimal performance may have as much to do with that as anything else. What level of service are you paying for, from which provider, etc.?