Look into ergo grips or ergon grips - those might help with numbness.
http://www.rei.com/category/4500112?...FQuB5QodTnBLNw
You also want the shifters aligned on the handlebars so that your wrists are in a neutral position while you're holding the handlebars or shifting/braking... the shifters/brakes can rotate around the bar - so you want to make it so that you dno't have to bend your hand back towards you while holding on to the bar - keep your wrists/hand position straight.
There's a ton of threads on here about what to do about hand numbness/pain - but possibly those 2 will helpyou.
The other thing is that as a new rider you're still "building up your core" muscles - when riding a bike, even if you're leaned over you really don't put your weight on your wrists - you support your weight with your back/core but you're not leaning on your wrists - until you build up your core a bit, you're probably leaning on your wrists too much and that's going to contribute to wrist numbness.
Nearly always you have to replace the stock seat on bikes, so check and search for teh threads on how to measure your sit bones and chose a saddle.
I hope this helps!