According to Closer, the glamour model also hopes that having perkier breasts will help her win another shoot with Playboy magazine.
"Katie's planning a total makeover on her return from her holiday in Marbella next week," a source told the magazine.
"She's desperate to make herself into the perfect woman for Leandro, who has told her he prefers a more natural look."
They added: "Katie is going to go down a cup size to a D and says she wants pert boobs so she can do another Playboy shoot.
"Katie knows that she's never going to find Mr Perfect - he doesn't exist - but she's hell-bent on not letting Leo walk away, and hopes that making herself look the part will encourage him to pop the question."
Last month it was claimed that Price wants bottom implants to impress Penna.
A poll conducted last year suggested that Price has the worst-looking celebrity breasts, with voters describing her cosmetically-enhanced chest as "tacky" and "unattractive".
> Katie Price: 'I look best when I'm natural'