Help Wanted: PHP form with sendmail authentication

I was using a simple php contact form in my proxy site. It was all working fine.

But now my hosting company says that they have disabled using nobody from sending mails. They require SMTP authentication to send mails.

Here is my Code what I have now.

Where do I include the SMTP authentication in this form. W'd really appreciate your help.

 

try phpmailer

 

Thanks for replying, I will check it.