how do I remove/replace garbage disposal ?

Good morning Helen,
URGENT! FIRST SWITCH IT OFF AT THE WALL SOCKET
If it is connected via a plug on the end of the lead pull the plug out.
If it is a wall fitting with a switch but no plug it should have a little fuse panel. SWITCH IT OFF then leaver out the fuse panel with a small screw driver and remove the fuse. put the cover back.
Tape a note over it saying the fuse has been removed.
If it's not a plug you need to be or get in someone who is competent with electrics to disconnect the lead.

Emerson is a USA company, and did make an E101. See this link for comparison.

http://www.amazon.co.uk/Emerson-Insinkerator-Garbage-Disposer-E101/dp/B002KVLNXU

For service and support check this link

https://insinkerator.co.uk/service-and-support

If it is leaking internally then I would say it is a terminal problem and suggest it is renewed or as you say replaced with sink wast and new pipework. But it may only be the seal between the unit and sink or sink waste.
To check this, with the sink empty, pore water directly into the waste, (without it going in the sink) and not up to the top of the unit and then check if it is leaking.
If it is, an internal seal is probably gone.
If it is not leaking at this stage poor in more water until it starts filling the sink, check where its leaking from. This should give you an indication.
Before I go into it in depth how handy are you at DIY? It's not a difficult job if you have the tools and a little knowledge ;-)
And what town of the UK are you in?
Hope this helps for a start
Regards John

John
December 2014