David Hoskins is a reasonably common name, and there may be many artists with that name. Without seeing the painting in person it is impossible to give an accurate approximation of its likely value. You might try looking on eBay or some of the live auction sites to see if you can find work by the same artist. This should give you an idea of possible value. Please bear in mind that there are huge numbers of amateur artists who produce amazing work that has very limited resale value.