Communicate with the seller. Ask if he's willing to let a non-US buyer bid for the item but have it shipped to a US address (Vpost in your case). If need be, convince him that you're a a verified paypal account holder and you are able to pay via paypal (seems more attractive to sellers compared to other forms of payment). You can go to vpost website to calculate the rough shipping cost provided you have the dimensions and weight of the item.
If it's anything more than US$2500, it'll be damn troublesome as you'll need to get the seller to fill in a Shipper's Export Declaration form (check Vpost's FAQ for details) in order to ship it out of US. I've just purchased a guitar online and had helluva lot of trouble getting it shipped here cos it's more than that US$2.5K.
Usually, I'd just ask the seller if he's willing to ship it outside US and try to convince him that you're fine with paying for the international shipping. I'd only use Vpost on a last resort.