Bringing power to a newly constructed detach garage
First.  Next time you're welding and a breaker trips, put the tool down, walk away, and don't use the tool again until you have corrected the wiring defect (i.e. too-small wire for the tool and a breaker that is correct to protect that wire).

Talk to your power company about uploading that meter

Normally I would say "no way" because the meter itself and the service lateral (the pole line/underground from the transformer) would also need to have the capacity, and it usually doesn't. 

However yours sounds like an all-electric house.  I've seen all-electric houses provisioned for 400A.  So it's possible the power company has already dropped a service lateral fit for 400A. In which case yeah, you could feed a second 200A main breaker right next to the meter pan and have that feed the garage.  

Otherwise you will need to upgrade service, and depending on costs you may be better off getting a separate drop/meter. 

This is completely determined by the power company and their peculiar situation on your block, we cannot possibly advise you other than to talk to them. 

Given a project of this scope and safety impact, it goes without saying that you must communicate with the power company and must also pull permits with your local AHJ and do the inspection rigmarole.  Generally AHJs are ok with people doing their own work, provided  they are not a landlord (in which case no) or working commercially (in which case maybe).  Doing this "gypsy" is out of the question. 

You need to know more about exactly what your loads are

It sounds like you have only a coarse grasp of the electrical loads in your house.  It is time for you to do a proper survey.  

You are looking for watts or VA and need to eventually turn that into  amps by dividing by volts.  For instance a 2000W heater which runs on 240V is -- anyone, anyone, Bueller?  8.3333 amps at 240V. 

For a resistive heater, Watts and VA are identical.  For most others, VA is more important - Watts is what you pay for, VA is what trips the breaker. (to be more precise, VA is the power you must provision.)  When different, use VA. 

Get the numbers off the machines' nameplates.  If no nameplate and they plug in, just get a $30 Kill-a-Watt and measure the machine underway.  You'd be surprised what is almost nothing (coffee grinders) and what is a lot (coffee makers).  Kill-a-Watt is not as helpful as nameplate, because nameplate is professionally tested. 

Motors are special; get their running amps and horsepower.  Locked rotor amps (a rather large number compared to the others) is not that important, nor is RPM. 

Make a spreadsheet of the whole kit-n-kaboodle, you can do 240V and 120V loads separately.   Then think about what is likely to be on at the same time (NOT heat and A/C hopefully) but even moreso, in the shop.  Do you expect to use the lathe and planer at the same time? 

Once you have done this survey, a bunch of really educational numbers will fall out the bottom and you'll know what to do next.  

Think more about conservation

LED bulbs are nice, but it is "rearranging deck chairs on the Titanic" if you have resistive electric heat.  I would go one of two ways on that.  One is convert your resistive heaters to heaters that mine Bitcoin - you're still using a lot of electricity but at least you're getting paid.  The other is go heat pump, which is ideal in a place freezes are rare; this will greatly lower your energy consumption and give you more headroom to run the shop.