If you can't find garlic cheese spread in a jar or in a roll, you could use velveta and add garlic powder or for a slightly different flavor, the mexican style velveta.
If using the garlic cheese roll or velveta, cut into chunks first. Place in sauce pan or fondue pot with the bean soup. Heat slowly, stirring constantly, until well blended. Stir in sour cream and onion. Heat through over low heat. Serve with crackers, tortilla chips, chunks of french or rye bread. Keep warm while serving.