As few as a handful of raisins or grapes can make a dog ill; however, of the ten cases reported to the ASPCA Animal Poison Control Center (APCC), each dog ingested between nine ounces and two pounds of grapes or raisins
If your dog has ingested large quantities of raisins or grapes, (s)he will immediately begin to vomit repeatedly, and will become extremely hyperactive and jittery. After about 24 hours, the dog will become lethargic and depressed. (S)he may experience abdominal pain and may stop urinating, drinking, and/or eating. (S)he will also become dehydrated. Both his/her vomit and feces will contain partially digested raisins or grapes. His/her breathing may become irregular, and (s)he will also become hypercalcemic (high calcium concentrations) and hyperphosphosphatemic
http://www.dogbreedinfo.com/grapeandraisin.htm
hope this helps, and he/she is ok!!