Which router should I use to replace 4331

[ArshdeepDhillon]

Hi, I have to help my client they already bought 3 routers for 3 buildings. WAN connection is 4331 and other building connecting to it are 4221. But as 4331 only has 2 ports. Should I add module for more ports or replace 4331 with 4431? And do I have to buy license for 1GB connection to buildings? 

Like WAN connection to 4331 is about 500MB and this connects to other buildings with fiber to 4221. Do i still need to buy performance license to get 1GB connection to each building?

Thanks for your help.

[Leo Laohoo]

4331 cannot push 500 Mbps. 4431 can push 500 Mbps.
Get a SM-X-4X1G-1X10G.

[ArshdeepDhillon]

So should I keep 4331 and buy the card you suggested? what about this NIM-2GE-CU-SFP would this work with 4331 I mean do I need to buy performance license for this one?

If I get 4451 would I need to buy anything else?