The cheapest and least problematic way to do this is for the long run is to get rid this router and buy one that is on the XBox Live compatability list. Routers are inexepensive these days. I have include a list of compatable routers along with incompatable routers. (Netgear Wireless looks good)
Routers
The following routers have earned the Xbox Live Compatible logo.
Microsoft Supported Firmware Wireless Standards
MN-100
1.08, 1.11.017
Wired only
MN-500
1.08, 1.11.017
802.11b
MN-700
02.00.07.0331, 02.00.08.0333, 02.01.02.0590
802.11g/b
D-Link Supported Firmware Wireless Standards
DI-524
1.05, 3.00
802.11g/b
DI-604
2.18, 3.2, 3.36, 3.51
Wired only
DI-614+
2.18, 3.2, 3.35, 3.43
802.11b
DI-624
2.25, 2.28, 2.42, 2.50, 2.70
802.11g/b
DI-634M
2.01
802.11g/b
DI-784
2.38
802.11a/g/b
DGL-4100
1.2, 1.3, 1.6
Wired only
DGL-4300
1.2, 1.3, 1.6
802.11g/b
WBR-1310
1.01
802.11g/b
EBR-2310
1.00
Wired Only
Linksys Supported Firmware Wireless Standards
BEFSR41 (v3)
1.04.8, 1.05.00
Wired only
BEFW11S4 (v4)
1.45.3, 1.50.14
802.11b
WRT54G (v1, v2, v3)
3.01.3, 3.03.6
802.11g/b
WRT54GS (v2)
3.37.6
802.11g/b
WRT55AG (v2)
1.10
802.11g/b/a
Netgear Supported Firmware Wireless Standards
WGU624
1.0.1.2EN, 1.0.1.9EN
802.11g/b
WGR614 (v1)
1.40
802.11g/b
WGR614 (v5)
1.0.7_1.0.6
802.11g/b
WGR614 (v6)
1.0.11_1.0.7
802.11g/b
WGT624 (v2)
4.2.6_1.0.1
802.11g/b
WGT624 (v3)
1.0.12_1.0.1, V1.0.120_1.0.1, V1.0.128_1.0.1
802.11g/b
WGT634U
1.4.1.8, 1.4.1.10
802.11g/b
WPN824
1.0.10_1.0.7, V2.0.15_1.0.11
802.11g/b
ZyXEL Supported Firmware Wireless Standards
X-550
X-550_V1.1
802.11g/b
Incompatible Routers
These routers have been found to be incompatible with Xbox Live.
D-Link Linksys Netgear SMC
DI-754
BEFSR11
MR314
7004VBR
DI-764
BEFW11S4 (v2)
RP114
7004WFW
NR041
RP334
RT311
RT314
Wireless Bridges
The following wireless bridges have earned the Xbox Live Compatible logo.
Microsoft Supported Firmware Wireless Standards
MN-740
1.0.2.21 and later
802.11g/b
Linksys Supported Firmware Wireless Standards
WGA54G
1.10
802.11g/b
WGA54AG
1.0
802.11a/g/b
WGA54G (v2)
1.6
802.11a/g/b
Gateways
The following gateways have earned the Xbox Live Compatible logo.
Model Supported Firmware Wireless Standards Logo-Certified With
Siemens/Efficient Networks Speedstream 6300
3.0.2 (004-E771-A3Z), 3.2.0 (004-E771-A5X)
802.11g/b
Sympatico (Bell Canada)
Siemens/Efficient Networks Speedstream 6520
4.0.0c (004-E752-A4E config 003-w093-G0A), 4.2.0 (004-E752-ABS), 4.2.0b (004-E752-AEJ)
802.11g/b
Sympatico (Bell Canada)
Netgear CG814WG
2.94d02
802.11g
Comcast
Actiontec GT701R
QW04-3.60.2.0.6.3-GT701
802.11g/b
Qwest
Actiontec GT701WG
QW04-3.60.2.0.6.3-GT701-WG
802.11g/b
Qwest