Help with HD Video Streaming

Hi,

I recently purchased a slingbox pro hd to be used with a slingcatcher in a different part of the world. I am trying to determine if I just need 1 new router or a seperate network set up in the location of the slingbox. Here's a breakdown of how everything is currently set up:

In NY:
Verizon Fios Internet 35 Download/20 upload
Belkin G speed router
Slingbox Pro-HD plugged directly into the verizon modem
1 desktop directly plugged into the verizon modem used for normal internet use
1 lap top accesses the system wirelessly for normal internet use
1 desktop located in the lower level of the home that catches a signal from the wireless router to get an internet signal

In Dublin Ireland:
UPC Internet on a 20 download speed
1 DIR-655 wireless router
1 Slingcatcher plugged directly into the router
1 laptop used for normal internet usage usually either plugged into the router or accessed wirelessly

The problem lies that I see a signifigant decrease in picture quality when the internet is being used in NY. Last evening, I had to lower my slingcatcher setting to the lowest quality, basically of a YouTube video to get a consistent picture while the others in NY were using their computers. If I compare that to this morning when noone was online in NY, I was getting a practically perfect HD picture in Dublin.

Before I start going out and making purchases, I wanted to see if you all think that something like a DIR-655 router (unless you have advice on something that would be better) in NY and have everyone going through it including my slingbox would correct my issue, do I need to get a seperate network in NY only for my slingbox, or could it be something else? Any help would be greatly appreciated!