As a couple of the others have pointed out. The answer lies in using SNMP which the Prolink should support.
You will need to look in the prolink's settings for SNMP references. Ideally using SNMP v3, direct the output to the IP address of your PC.
Then you need some receiving software on the PC. I've used the Kiwi Syslog Server before because it is easy to set up and use. It isn't free but there is a trial which works fine for 14 days which may be enough. Otherwise there are several other tools that can be used including PRTG Network Monitor (which has a freeware version).
You will then need to familiarise yourself with the various counters that the router produces. This is easier if there is a Management Information Base (MIB) for the router but you should find that your SNMP viewer software will have a generic router MIB that should suffice. It generally takes a bit of experimentation to find the most appropriate counters.
You should now be in a position to monitor the throughput of the router.
If you want to do this kind of monitoring with Wireshark, you need a Promiscuous Mode driver for your LAN connection and you need the monitoring PC to be in line with the data that the other PC's are sending to the router. In the days before switches were common, this was easy. These days, the easiest way is to make the PC into a router (for which you need two network cards) and force all the traffic through the PC - probably not something you want to mess with quite honestly.
The third method to do this would be to get the information direct from the PC's. However, this would require you to be an administrator on the Windows network in use (or have administrative rights on each PC). You can then use the built-in remote admin and monitoring tools provided by Microsoft to monitor each PC's use of the network.
Bear in mind when monitoring bandwidth, that you will never get better than around 80% utilisation of a network.