No welding, your just going to ruin the block surface. There is no bolt left to weld on....

Clean the area up and take another picture so we can see whats going on. Don't go crazy with a rough sand paper to clean it up, use something soft.

I would block sand that 600 grit til you can figure out what is going on.

Here are more pictures, as I steaed earlier I am new to MIG welding, the sparks are very bright/ blinding. It is now clear that the MIG tip has created a few "pitting marke" into the sealing surface, I am not going to try welding my self again. Now I need an experts help. How do I find a professional? some one who can come to my house and take care of this? any suggestions? craiglist?

I've been a cetitfied welder for over 50 years! You can no longer weld it, weren't you wearing a hood?
Now you need a die-grinder, if you have air, or a Dremel tool, and some carbide cutting wheels. Pull the radiator out to give you more room to work, and cut the stub off flush with the block. Don't cut into the machined surface of the block. Dremels are variable speed so slow is the way to go. Then refer to my post #30. There's no quick fix for this now. You need to be patient, and take your time. If you don't have the mechanical skills for this, then you need to have the car taken to a pro, like Greg Nettles. Pull that gear and get it out of the way too.

I would be cutting it flush, center punching, then drilling and extracting, or retapping.