I am only getting 65mbps for my 300mpbs wireless n router.. y?

1. You need to ensure that your wireless network adapter (your wifi network card in your PC / Laptop) is capable of handling higher speeds, and N technology (some wifi adapters are limited to B & G, or 150mbps N).

2. You can also try modifying the channel frequency on the 40Ghz range and seeing which "clean" frequency provides the best connection stability in your area, especially if you are in an area with a lot of wireless / wifi signal interference.

3. You need to try keep note on how many walls / barriers are in-between your pc / laptop and the wifi router, as any obstruction will reduce the connection strength between the two devices.

4. Keep in mind that unless you're using LAN connectivity speeds, or have a 10mbps > internet connection, a stable data rate of 54mbps will be more than sufficient for transmitting and receiving your data over indoor wireless.

Remember that the only difference with your data throughput rate is the amount of data able to squeeze through your wireless connection at a given time, for example, 150mbps would be ~18mb/s in terms of data throughput - unless you're copying data via wifi from PC-to-PC / Laptop-to-PC / etc., then your internet traffic shouldn't be that badly impacted. (setting aside physical interference such as walls as a cause for poorere latency / response time)

You can download InSSIDer and it will snoop all the wifi near you and what channel they are running on so you can find the least congested channel(s).

http://www.metageek.net/products/inssider/