are there any buses or car with driver for rent in Chengdu

Oh, yes. TravelChinaGuide provides car rental service.
The price is reasonable and the service is high-efficiency. They have professional drivers and English speaking guides. So you can trust them. The contact information is traveltravelchinaguide.com.

As for the accommodation, you can go to Hualong Hotel. The price is about CNY 200 to 300 per night. It has comfortable living environment. You can easily find this hotel in this scenic area.

Generally speaking, you need two days to tour around if you wanna cover every must-see. :-)

Actually i already took 8days tour in jiuzhaigou,see panda,mt emei leshan,huang long xi ancient town, song pam ancient town,jinli pedestrian street.but i extend for 1 night more.the last day that i joined the tour stay in howard johnsen agile plaza hotel. I have plan to.go.to huang.long and mu ni gou.are there any suggestion place?

Since you joined the tour in the hotel, don't they offer a van or bus for all tourists? If not, you probably should take Jennis' advice. The travel agency will arrange a car or van with a driver (as well as a tour guide if you need). You will enjoy your trip in Huanglong and Munigou.