Speed can be a function both of how fast you receive and send data (basically your Internet connection) and how fast your computer can process what it gets. We need some details on what makes you think it is slow.
My Mac is about 10 years old and still handles the Internet okay.
What do you mean by it is slow? What are you doing? Typign e-mail or streaming Netflix? How fast a connection do you pay for with your ISP? Have you run a test with a service such as Speedtest or Speakeasy to see what connection speeds you are seeing?
A few general observations which may (or may not) have something to do with your speed.
First, I see your signal strength is pretty low at -80dB, though your noise level is about normal low at -96dB. Still, with a weaker signal you may not receive data as easily an it has to be sent several times.
Second, I see you are using channel 9. In the USA there are 3 truly unique channels, channels 1, 11 and 6. Most people use one of these three. If you are using channel 9 and have lots of neighbors then you are interfering slightly with users of both channel 6 and channel 11 and may see degraded connection speed. I have neighbors who use the same channel as I do and at times I lose Internet altogether.
Thanks for the quick response! I'm a med student and watch a lot of streaming videos for school and they constantly stop playing to buffer, or the video will say connection lost (even though I'm still connected to the internet - it's just going very slowly). I use Comcast for my cable internet. After doing a speed test (through Comcast's website), it said my download speed was 12.69 Mbps and my upload was 4.18 Mbps. In terms of signal strength I'm only maybe 10 or 15 feet away from my router, which is a few years old - so maybe that's in need of replacement? Also, for the channel selection on my router, would you recommned I change that to "auto", or just play around with them until I find one with the least interference from the neighbors? Thanks for all your help!