At auction, Sports Roadsters generally sell in the $25,000 to $50,000 range - depending on all the usual variables: how nice (and original) the car is, who's in attendance at the auction, how the economy is doing, etc. Your car appears to be in very good condition, so I'd guess it would sell on the high end of the scale.
Where to sell? Any of the 'big' auctions (Mecum, Russo & Steele, etc.) generally get good results, but you have to transport the car to their auction site, pay a hefty commission and hope that an interested seller is either there or watching the auction. Ebay is also a possibility, but they're pretty expensive and you have to jump through their hoops...
One new auction group that's become popular lately with sellers of collector cars is an internet site called
bringatrailer.com . They are much more reasonable in their charges and have the advantage of an audience that's made up almost completely of 'car people' (both individuals and dealers). If I were you, I would check out their services - just sign in and watch the action for a few days or weeks. Although I've never bought or sold a car through them, they do get excellent reviews.
As far as selling overseas goes, it's becoming a more and more frequent occurrence. If you're a member of most on-line marque forums, there will be members who have already sold a car overseas and will be able to give you guidance to help you avoid common pitfalls.
In any case, good luck with your sale!
Dave B.