|The problem could be the network interfaces on the computers connected or the router itself.|
Assuming your router's LAN ports a 100 Mbps (bandwidth is always in multiples of 10...ie: 10/100/1000/100000 Mbps) and set to "Auto" as long as your PC and laptop's interfaces are 100 Mbps or better, you should be connecting at a full 100 Mbps. Check each connected device for what they are connected at. If one of them is connecting only at 10 and the others 100, then the issue would be with the NIC of the device connecting at 10. You could try forcing it to 100 to see if that works. If not, then there may be hardware issues with the NIC.
One thing you could also do is to update the drivers for the network interfaces on all your PC's.
You have a couple options available to you. Assuming your computers network interfaces are all 1000 Mbps capable you could:
1) Buy a small 1000 Mbps switch and connect all computers to it and it in turn to the router. This would give all devices connected to the switch 1000 Mbps bandwidth while allowing them all internet access
2) You could purchase a crossover cable and directly connect all devices in turn to the one you want to move data to.
Lastly, you could buy a RAID capable NAS device (network attached storage) and connect it to your LAN and move your data to it. The big advantage of a NAS is redundancy. I have a small two hard drive NAS at home with two 2 terabyte disks in it that are in a RAID 1 array. Should one disk fail, I simply replace it, rebuild the array and I lose no data. I do all my computer backups as well as store all data I do not wish to lose to the NAS which frees up HDD space on my PC's.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.