Two repairs are needed for my X51 System; what should i do?

Hello,

I need two repairs for my system, but am unsure about how to get them fixed.

First Issue: When I had a Dell Technician come to my home and fix both the high-pitched fan noise and the front bezel on my X51, it seems that the case was not properly put back together. To replace the bezel, the entire system needed to be taken apart and this technician had never even seen an X51 before. In the end, the side panel was not snug along the system. I never noticed it until I looked at my system closely:

I don't know how to fix this. I tried several times to put the panel on but to no avail. I suppose to fix it, the system would have to be taken apart again?

Second Issue: My wireless has been really weak, jumping around from 2-3 bars and rarely 4 bars, but I am only 2 metres away from my router. I read and found out that is has something to do with my antenna (I have the earlier grey antenna) and I have the Dell Wireless 1502 Card. I suppose the replacement part is the 1506?

How would I go about getting these issues fixed? Would I be able to send my pc into Dell and they could fix the my pc? How long would It take? I doubt the case can be fixed by a technician. By the way, I bought my system in early February, and I live in Canada.