Ready to upgrade your Wi-Fi router. 802.11n should be your next choice. A few years ago the standard was shady and most people warned that products would not be upgradable. But now the gap is closing in on 802.11n draft and all new compliant 802.11n draft should be upgradeable, just make sure it's certified compliant.
Wireless LAN Throughput by IEEE Standard
IEEE WLAN Standard Over-the-Air (OTA) Estimates Media Access Control Layer, Service Access Point (MAC SAP) Estimates
802.11b 11 Mbps 5 Mbps
802.11g 54 Mbps 25 Mbps (when .11b is not present)
802.11a 54 Mbps 25 Mbps
802.11n 200+ Mbps 100 Mbps