1995 Toyota Tercel Stalling

Okay. So last Tuesday I bought this car for $1050 from a dealership. They told me that the EGR Vacuum Switching Valve needs to be replaced. I have gone through one tank of gas. I put Carb Cleaner in with the gas like the bottle says to do. I took it to the Mechanic and had them replace the timing belt and water pump. They forgot to re-connect my brake assist. So I took it back and they connected it. The thing that is happening now, is that when I am at a complete stop, and put my car into first gear it sounds like it is about to stall. Sometimes when I go into second gear it shakes and lurches forward. But when the car gets into a higher gear such as third and above, it runs fine. I had a tune up done as well. Replaced the spark plugs, and the spark plug wires, and put in a new air filter. Also got the oil changed. It is still doing this. What would be causing this issue? I know nothing about cars, and the mechanics are talking about my ignition and what not. I don't know what is going on with my car! I've already invested over 600 dollars of repairs into this car. Help Please!