How to use a group by in a subquery

[Sarah Smith]

I am trying to create a query that will return the athlete's id, their first and last name in one column, the number of games they have participated in, and the number of medals they have won.

So far I have this code:

SELECT ATHLETE.Athlete_id AS ID, (ATHLETE.Athlete_lname+", "+ATHLETE.Athlete_fname) AS Name, COUNT(REPRESENTATIVE.Athlete_id) AS [# of Game], 
(SELECT COUNT(MEDAL.Cont_id)
FROM MEDAL, ATHLETE, CONTESTANT, REPRESENTATIVE
WHERE MEDAL.Cont_id=CONTESTANT.Cont_id 
And CONTESTANT.Rep_id=REPRESENTATIVE.Rep_id 
And REPRESENTATIVE.Athlete_id=ATHLETE.Athlete_id
GROUP BY ATHLETE.Athlete_id
HAVING COUNT(MEDAL.Cont_id) > 0
ORDER BY COUNT(MEDAL.Cont_id) DESC) AS [# of Medal]
FROM REPRESENTATIVE, ATHLETE
WHERE ATHLETE.Athlete_id=REPRESENTATIVE.Athlete_id
GROUP BY ATHLETE.Athlete_id, ATHLETE.Athlete_lname, ATHLETE.Athlete_fname;

It is doing what I want except the results from the subquery are not grouped. I want them to be grouped by the athlete, however, whenever I try it says that "at most only one record can be returned by this subquery".
Any help would be greatly appreciated