Jeep safari booking in Pench

I need quick help pleeease.
We are going to Pench on 23rd and have already booked 3 safaris ( M & E on 24th, and M on 25th), returning on Sun afternoon. These safaris were booked thru our resort and cost Rs 3500 per safari. I know that they charge more but thought, ok, makes life easier.
Now our flight reaches Nagpur at 1.00pm, ( no checked luggage) and hopefully we should reach the resort around 3.00- 3.30pm (if we are lucky & dont run into traffic jams!!)
The thing is, we would also like to do the evening safari on that day even if its a shorter ride. I don't want to pre book this safari thru the resort and waste Rs 3500 in case we don't make it. I was looking at 1 other option, to book online thru the official MP website for which the charges are Rs 1500 and losing this amount in worse case scenario doesnt seem too bad.
My question is this: On the website there's an option "registered vehicle/unregistered vehicle" - I want the former option. Now after the booking how do I get to the driver/vehicle/guide? Do I choose any vehicle at the Touria gate or do the forest authorities allot a jeep if I show them the booking form?
Need a reply faaaast! Thanks in advance.

3500 per safari only !I think it's inclusive of everything.Your hotel will arrange the gypsy for you.
So,make it clear first.
I visited Pench in Dec-2011.If you want I can PM you the mobile number of the driver that we took.You can have a chat with him.

I would suggest please check with www.traveladiction.com even they provide good info about your destination that too at very less price @ Rs100 or $5 only. You can mail them at inof@traveladiction.com they usually reply in 48hrs.