You could use multiple ports or upgrade with NBASE-T based NICs. This will support 10/100/1000/2500/5000 using CAT5 (or better), up to 100m.

In the future you can upgrade to 5 Gbps. The tech is beginning to hit the market. Cisco started shipping switches last summer. Intel will be supporting the new NBASE-T speeds on their NICs (2.5/5.0Gbps).