How big can I print this image

[Elle26]

I think this is going to be bad news but I have to ask anyway

I want to print this image as a present as large as possible but I bought it off a lady who took it years ago with a basic camera. 

Whilst I have worked out on PS that it is over 17 megapixels, when I zoom in i'm not getting any focus!

If you don't have the focus is there a guide of how big this will go?

I went to so much effort to purchase this image and I'm going to be so shattered if I can't print it! 

[Damien Symonds]

Oh gee.  That's been artificially enlarged a long way, hasn't it?  That's really awful.

If you're going to print it, I suggest canvas.  Canvas is more forgiving.  But even then, I wouldn't go very large.

[Elle26]

So disappointing. 

I paid $75 for it and it was only after that that she said it was taken on a point and shoot which was about 12mp

She also said that she changed it to 300dpi. Would that have changed things?

There is nothing I can do to save this is there??

Thanks so much for your help!

[Damien Symonds]

She is pulling your leg at 12 megapixels. I'd say 4.

I would demand a refund.