That is a tough call, but if it is only an upper respirtatory infection it won't be urgent, but if it turns into pnuemonia- which it is always possible, you will need to go......
.....Options you have is to do some steam treatments in the bathroom. Using a digital thermometer check his temperature in his rectum (aka butthole) and it should be around 99-101.
Upper respiratory infections are common in puppies, but if it is accompanied by a cough it is likely kennel cough.
If it is higher than 102 or if he becomes lethargic, won't eat, ect. you MUST get him to the ER. But with a brand new puppy, I wouldn't take any chances personally and I would get him in right away anyway.
Good luck, and keep us updated.