Information/Network Security Assessment/ Audit professional Course

yes u must go for
Cisco Certified Security Professional - CCSP

The Cisco Certified Security Professional (CCSP) certification requires five exams:

    642-501 SECUR
    642-521 CSPFA
    643-531 CSIDS Beta
    642-511 CSVPN
    642-541 CSI

The exams are based on the following Cisco courses: Securing Cisco IOS Networks (SECUR), Cisco Secure PIX® Firewall Advanced (CSPFA), Cisco Secure Intrusion Detection System (CSIDS), Cisco Secure Virtual Private Networks (CSVPN), and Cisco SAFE Implementation (CSI).

You can buy the following books
CCSP CSI Exam Certification Guide (CCSP Self-Study, 642-541) (Ccsp Self-Study)
Cisco Networkers 2009 BRKCRT-1280 CCSP Securing Networks With ASA Advanced SNAA Technical Introduction

Well for, Network Security Assessment/ Audit professional i recommend that you take
up CISA (Certified Information Systems Auditor) by ISACA.

The CCSP certification is more for technical specifications. If you are managing and implementing security devices then go for it, else for auditing CISA is ideal. Once done with CISA you can go in for CISM (Certified Information Security Manager)

CISSP is also a good option, but CISA will help you in assessment and audit profession. maybe once you are done with CISA go in for CISSP and then CISM.

For CISSP you can use the CISA exam for reducing the 5 yr experience to 4 yrs, and once you have CISSP, you can use your CISM study time to claim for CEPs for CISSP. (CEP - Continuous Education Programe)

I am a CCSP and also have a Web security Security for Field Engineers certification from CISCO.
I do not have a long experience in security field. i am just a beginner in it. Does the experience is a factor in taking CISA certification..??

Its always recommend to have some experience in the field
Only certifications are not enough unless you have hands on experience
I never hire the guys with certifications and no experience