Upgrade Nikon D3200? Or buy better LENS to perform as FullFrame?

I bought my Nikon D3200( 18-105 DX) around November 2012. I'm not a professional photographer, but would love to develop my pictures taken as that of a full frame output. When i bought my camera i didn't know the term sensor crop/ full frame. With time the use of Nikon D3200 in my hands has improved, and i feel the need to go for better lens for crispier and lenght of depth pictures. While hunting and researching for an additional lens for my D3200, i came across the full frame factor. Now, i'm in a fix, whether to upgrade My D3200 to full frame body or to go for additional lenses. I like taking pictures while travelling, and also landscapes, monuments, buildings, peoples, market etc. I'm not into portrait and studio photography. Can you recommend me on this issue as budget is another factor for all the above mentioned reasons. I Can't afford a Brand new full frame camera. Please ADVICE.

I do not think it is anywhere near worth the price of you buying a full frame camera. I feel it would gain you little to nothing. The main advantage would be some cleaner photos in dim conditions at high ISO speeds. Good lenses would do more for you. Your lenses are an investment that lose very little value. Digital camera bodies come and go and what is the "latest and greatest" now will just be a cheap used body in a relatively short time. You can always change to a full frame camera at any time in the future. For now, I highly suggest your limited resources would be far better used on lenses.

If you compared the investment into a D610 or D810 and compared that to what you could get in lenses, then I think it's a no brainer. Keep your camera and get the type of lens that will allow you to capture scene in a way that matches that of your vision. Bodies will come and go, but good glass will always be good glass.
Furthermore, if you were to go full frame (FF), you wouldn't be able to use your current EF-S lenses.
Watch this video on APS-C vs FF by Zach Arias - it's pretty darn good.

Steve P has given you great advice. Can't add anything to that.

18-105 yuck yuck yucky. Go buy yourself a 35mm 1.8 and you will see the difference in image quality and you will obtain that lovely depth of field.

Thank you all for your help and advice. I'll stick with my Nikon body and look for additional lenses.