Possible stroke symptom?

[Konopka1955]

Hi, I recently (age 48) had OHS for my mitral valve and had to have it replaced with a St. Jude Mechanical valve.  I had rheumative fever as a baby that damaged my valve.  I had an MI in 1992 at age 37.  ICD inplanted for vt in 2001 - No bypass and Cath showed no increase in plaque in 12 years. :-)  

I've had a terrible time getting my INR stable.  Times I've been around 1.5 or 1.6. It was suggested that I take the lovenox shots..  But I hate needles. So, I took more coumadin.
Shortly after surgery I got occassional migrane headaches.  4 mos post op I now get a 'numbness' mostly on my left side of my face and my left eye feels like its been given a shot of novacaine..  It feels weird - but my vision is fine.  Once in a while I've had it on my right side - same symptoms.

Q 1:  Could the coumadin be causing my occassional headache or now almost a daily numb feeling on the side of my face?
Q 2:  Are these symptoms 'normal' after OHS - and do they usually subside in time?
Q 3: I see my cardio tomorrow - what kind of tests would rule out a possible TIA?  
Q 4:  If I go to the ER after the symptoms disapate - can they tell if I've had a TIA?  Are there any tests to tell if I've had a TIA?
Q 5:  Are there any meds I could take that might make this 'numbness' feeling go away?
Q 6:  Do you have any suggestions for questions to ask my cardio?
I run regularly and since my surgery in May I've run 6 road races - got two medals and other than this 'numbness' and my eye feeling swollen -  I feel FANTASTIC.  Really I feel great..
Thanks
Konopka1955