The 54 Mbps speed is the speed between your pc and your router. This is moderatlely fast.
Your Internet speed, even at the best likely speed of 10 Mbps from a CATV feed, is still a lot slower. I suspect your Internet speed is less than 10 Mbps. This is the slower link. If you want to purchase a faster service you may get a faster link.
Finally if you did not measure speed using a speed test web site, you may have been misled. Many think a downloading server's download speed is your internet speed. In fact downloading servers are throttled back and often decrease in speed as number of users increases.
Run a speed test from a web speed test site. If it is way slower than your service is supposed to be, disconnect router and run pc directly wired to the modem and run again. If it is still far slower than it should be contact ISP while you are linked directly to modem as something is in need of service by the ISP.