The 29-year old forward, who is back at Fir Park, after spells with Everton, Birmingham City and Sunderland has not played for the Scottish side since September 2010 and he is planning to impress new boss Gordon Strachan in order to reach his goal.
"I've got unfinished business with Scotland. I can't end my Scotland career on that note," he said.
"I'm only 29 and if I can get back playing games I feel as though I can add to the party.
"Getting 50 caps would mean everything to me. When I was a young boy one cap would have been enough for me.
"But the fact I'm only two caps off of 50 it's a big target.
"It's been hard to watch Scotland because I want to play. If I get a run of games for Motherwell then it's up to the manager.
"I have not spoken to him yet, but if the manager still feels he needs me I know I can add to the team.
"I would be delighted if he picked me, but the last Scotland squad had a lot of good players in it."