This is what we use. Works good but takes a long time and sometimes going over area more than once to get out some water stains if they been there for a long time. And using it over your head is a pain but still a lot better than bigger machines. Follow directions on the carpet cleaning liquid. If a little bit is OK a whole lot is better is not true for this. To many soap suds. Couple places where we didn't get dry as possible or was really dirty or stained shows up when it dried. We've had better results by following up with a regular wet dry vac, to get completely dry as possible. Also works wonders on other upholstery (chairs, sofa etc). If this thing doesn't get out your mess you have, I think it is time to replace. But would be my first choice before replacing overhead carpet. Worked for us. See link and be sure to read the reviews
http://www.target.com/p/bissell-little-green-compact-multi-purpose-deep-cleaner/-/A-12777897?ref=tgt_adv_XSG10001&AFID=Google_PLA_df&LNM=%7C12777897&CPNG=Appliances&kpid=12777897&LID=PA&ci_src=17588969&ci_sku=12777897&gclid=CIKIkKK4m7kCFa9fQgodrG4AHg