Hi  Siva,

Yes you can do it from the Cisco Security Manager , or you can try

Automatic Signature Update Guidelines

When enabling automatic signature updates, it is recommended that you ensure
the following configuration guidelines have been met:

* The router's clock is set up with the proper relative time.

*The frequency for Cisco IOS IPS to obtain updated signature information has
been defined.

*The URL in which to retrieve the Cisco IOS IPS signature configuration files
has been specified.

*Optionally, the username and password for which to access the files from the
server have been specified.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip ips auto-update

4. occur-at min:hour date day

5. username name password password

6. url url

7. exit

8. show ip ips auto-update

http://www.cisco.com/en/US/docs/ios/sec_data_plane/configuration/guide/sec_ips5_sig_fs_ue_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1079125

regards

Yesua