What TV do you have? Most TV speakers are worthless but not all. If you have a RPTV that has say 6" drivers it might work for the time being as a CENTER channel, not for fronts. If you have a small TV with chicklet speakers forget it.
Your receiver will do a 3 channel setup with left, center, right and it will output the rear information through the fronts. If you don't have decent speakers in your TV then look for an inexpensive center channel speaker to get you by for now until you can get some timbre matched 3 front speakers. Check Onecall's bargain page or look for JBL and Infinity blowouts from HK on eBay.