Can I still apply for travel visa when I am about to renew my?
Usually it is okay to take the old passport, with a still-valid visa, along with your new passport, when you travel. But if you are applying for a new visa and need a new passport too, and have to send the passport away to have a new stamp affixed in it, then it would be best to get the new passport first and then apply for the new visa with that one.