New Lenox police is on Lincolnway dispatch, (but is planning to move to Will County EDACS system more on that below). Fire is on Southwest Central Dispatch. You could hear those frequencies on just about any scanner.
Check the database here
http://www.radioreference.com/apps/db/?ctid=689 for the frequencies.
Will county is a lot of fun to listen to. It is a trunked EDACS system, so if you get a new scanner make sure it can handle that. Joliet is your neighbor and a lot of fun to listen to as well, and is on a Motorola trunked system. If you want to hear Illinois State Police you will need a scanner capable of Digital. Digital capability is where the scanners get pretty expensive.
A UnidenBDC396T will do everything you could ever ask for but it's a little expensive. A sponsor of this forum, Scannermaster, has a great website to research, and I have enjoyed doing business with them. Radioshack had their PRO-96 on sale recently, and it too will do pretty much anything. Be careful to get a scanner that supports rebanding (check the wiki) if you're going to invest in something. Both of these will according to current knowledge. Skip the Digital and you could consider a BR330T or a BC246T from Uniden or a GRE PSR300 for around $200 and have something worthwhile.
Modern scanners are programmed with a computer and software. Theoretically you can punch the buttons, but I think that's a little silly and difficult. It is possible to download frequencies directly from this website with a inexpensive subscription (although you can look at it and punch it into the software for free too), software, cable, and capable scanner. It's not that hard if you're a little techy....if you are not, pay someone like Scannermaster to preload your scanner for your home area. Radioshack will 'sort of' program one of theirs for free, but you'll find that programming pretty lame pretty quickly.
Your Midland 75-800 is a CB radio. It will not hear anything related to the fire or police anywhere.
Welcome to the hobby and the forum. Read the forum, the Wiki and the Database, ask questions when you get stuck. Lots of locals on here that can and will help you.
Eric