Do it yourself

I have a question about basement flooding and drainage (with two to three possible solutions I'd like to get your opinions on) First the problem: Whenever it rains hard here (about 4 to 6 inches in a 12 hour period - it happened twice in November) one of my basement rooms gets about an inch of water (about 40 gallons vacuumed up from the wet-vac). What I know so far: This basement room is an addition to the existing basement and the floor slab is 6 inches lower than the rest of the old basement floor, but is physically separated by a foundation wall and not accessible to each other.(I have two ways to go downstairs). The water is coming out from the slab foundation joint at one corner where the foundation wall separates the old basement and the new basement. The foundation wall that separates them used to be an exterior wall, and the new basement room was an addition. What I think is happening: First, I think that the city drains are overflowing and backing up my perimeter drain and flooding asaturating the drain rock and soil around it with overflow rain water, thereby forcing the water to travel through the slab foundation joint as the water level rises. Second, I think that when the reno's were done, the permiter drain tile was not properly connected for some reason, or the new addition basement slab is 6" lower than the old basement slab, thereby the perimeter drain takes a 6" dip down at the transition point, thereby creating the breach/compromise. The solution(s) 1. I could dig up the perimeter of my house and do investigative work and replace and/or install new drain tile and drain rock and waterproof problem: very expensive and very disruptive 2. Install a sump pump problem: even more expensive and more disruptive 3. Use waterproof hydraulic cement and plug up the breach using something like Aquaplug problem: the water may just end up going to another part of my basement instead of containing it outside 4. Divert the rain water leaders away from the permiter drain by having them drain (above grade) into a drainage area away from the house problem: I could be dumping 1000 gallons of water into a small drainage area, which could cause a mini flood into my neighbours yard. The advice I already got: I talked to a drainage pro and he said it should be done "by the book" (solution 1 and 2)hmmm. Do you mean by YOUR POCKET BOOK???? He wanted to do the most drastic and most extreme by digging up the entire perimeter drain and reinstalling new big O and new drain rock and then install a new connection to the city sewer. This would mean breaking up the permiter concrete pathways, destroying the entire planting beds and ripping up my entire front yard. Cost: ohh, maybe $10,000, could be more, but your house will be dry and it'll by dry forever, and it'll last a hundred years, AND you'll be HAPPY (wooo hooo!!!). When I told him that was a bit excessive for me he got very defensive and insulted me and told me "Don't waste my f %$# ' n time if you don't want it done right." yes, he actually said that. This is verbatim Another pro said that using a concrete waterproofing agent (solution3)should do the trick if it only happens during the absolute heaviest rainfalls. I works for the vast majority of bsaement leaks and this is a prime candidate for this application. No comment was made when I told him if the water could migrate to the other areas of my basement The other method would be to divert the rain water to a catch basin or drainage area above grade (solution 4) and have the water drain down naturally through to groundwater and gravity instead of having it drain to the perimeter drain. Sorry for the long post, but opinions greatly appreciated.