So I thought buying a switch to sit inbetween my fileserver and computer would get me gigabit transfers to and from the server but I'm still getting 97-99Mbps so I assume the traffic is still going down to the router and back up. What would be the cheapest way of fixing this? Also the switch is an unmanaged one if that matters. I thought about getting the cheapest router with gigabit ports and using it adhoc where the switch should be but I'm looking for input before wasting more money because admittedly I don't have any knowledge of networking at all.
I do not know whether it is even possible, but maybe you somehow ended up having computer and fileserver on different subnetworks. You can check that by comparing combinations of ip addresses and subnet masks from both machines.
Start simple. Remove everything from the network except the GB switch, computer and fileserver? Get high speed transfers then? If so start adding back in the rest of the gear until you figure out where the problem lies.
So your capping out at around 100 Mbps, you should be closer to 1000. Make sure you don't confuse Gigabits (Gb) Megabits (Mb) and Megabytes (MB). How are you measuring transfer? I think windows shows you Megabytes per second. A Gigabit is around 125 Megabytes, if I remember correctly. So if you're using Windows file transfer and capping out at 100 MBps, then you're pretty close to your theoretical ceiling.
There are also other factors like harddrive speed that will slow you down. Frosty has it right though, remove everything except the switch, server, and pc and check transfer speeds then.