How Can I Upload a file more than 1mb

Strange - the normal default maximum is 5MB, so it may have been changed in your web.config.
Have a look at web.config, and see if there is an httpRunTime section. If so, the values for the maxRequestLength property controls the max upload size, in KB.

<httpRuntime maxRequestLength="25096""></httpRuntime>

Sets it to 25Mb.
If there isn't a setting, or this doesn't help, contact your hosting service, they may need to change the value for you in IIS.