Help me choosing the right codec

product: Dual-Core AMD Opteron™ Processor 2218 HE
vendor: Advanced Micro Devices [AMD]
physical id: 1
bus info: cpu@0
version: 15.1.3
size: 18EHz
width: 64 bits
capabilities: fpu fpu_exception wp tsc msr pae mce cx8 apic
mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext
fxsr_opt rdtscp x86-64 3dnowext 3dnow up pni cx16 lahf_lm cmp_legacy
svm extapic cr8legacy ts fid vid ttp tm stc

The above description is the CPU details of my EC2 instance running on
Ubuntu. I am making a product which will record voices and stores it.
I am researching for a codec for use with my asterisk which will
consume low bandwidth. As of now i am using u-law codec in my asterisk
and the sound quality is pretty good i think. As per the bandwidth
usage chart i think g723 or g729 will be the best ones for my purpose.
I have downloaded the and files. Now i want to know
How should i go with this means how can i install this so that it can
work with my asterisk. I do not have any problem in buying codec
license but the quality and bandwidth usage should be considered. If
you think i should use any other codec please suggest. Any advice will
be entertained. Thanks in advance.