HELP!!!! WARNING LIGHTS - cooling system and oil pressure low

Can somebody please offer any advice for my 1998 Audi A6 Quattro 2.8L problems:

The car shakes when I drive and kind of stutters when moving and even at idle.

I have no heat all of the sudden

A red light came on today that means cooling system problem

A red light came on today that means low oil pressure

The windows uncontrollably fogged up today.

I have a full tank of anti-freeze and full oil

Should I be putting premium or regular fuel in it?

I don't know how much I have to do in repairs or how much it would cost. The car has 95K miles. Any suggestions from anyone? I can't afford $3,000 in repairs. Please let me know if any one knows of cheaper alternatives.

Thanks, Joe snipped-for-privacy@aol.com

Check to see if all the cylinders are firing. Possible broken spark plug, bad plug wire. Do these have the infamous, intermittent, coil packs?

Heater core is bad / leaking. Repair cost will get your attention. If it is minor leak an additive like stop leak can be a temporary / semi permanent fix. However, from what you describe it sounds like the leak may be more than minor.

Don't drive until you know why this is on.

See comment on Heater core.

Heater core leak can fog windows with very little coolant lose.

Oil pressure my be causing the code. Is it cold where you live? Have you changed to winter weight oil? Use a good Mahle oil filter or have you taken the car to Jiffy Lube where they use Audi killing Fram or other cheap filters.

Follow recommendations of your owner's manual.

If you do not do your own work you should ask around and find an independent shop that specializes in working on Audi. Be sure to ask other Audi owners in your area for their opinion on the independents.

How does $2,999 sound? You might get by easier but when things break money flows.