HTPC Network Opinions

For the past two years i have slowly been converting my desktop into an HTPC. First while i was living in an apartment i purchased a Hauppauge WinTV 2250 Tuner and had basic cable running through WMC7 to dvr tv and used an Xbox to extend it to the living room. I combined that with media browser to share my computers media.
It worked ok, a bit slow on the xbox, frustrating how long it took to load up the mediabrowser menu’s and things and fast forward or rewind was useless.
Since then we have had cable boxes at home and stopped using wmc/mediabrowser and switched over to XBMC which I love. My desktop is now at an HTPC role 95% of the time in the living room.

Well now we just purchased a new house and plan to expand on what we have. I just placed an order for fios and do not want to give Verizon any money on cable boxes.

I need your opinions as to what I should be concentrating on or if it even possible to get what I need. I want to have two tv’s, one in the living room, one in the bedroom and be able to watch cable/dvr and have access to my xbmc library.
My current computer is a HP Pavilion a few years old (2009-2010) Specs:
Pentium Dual-Core E5300 @2.60ghz
4 gb of ram
Windows 7 64bit
With two WD my book usb 3.0 external hd’s
Unfortunately, the Nvidia graphics card that came with this computer burnt up and had to be removed so I am running the build in GPU which shows up as Intel G33/G31 Express Chipset Famly on device manager.
HDHomeRun Prime seems to be the only piece of my new setup that i am sure I am going to use.
Do you guys think that I should build a nice i3 HTPC and convert my current HTPC into a server? And maybe add a centon echo extender for the bedroom.
Any opinions are welcome. Thanks in advance.

Thanks for the info guys, so from what im putting together is that my current HTPC isn't that badly outdated and with a SSD it would make it even better. I would like to get away from using the xbox since i wont be able to share my xbmc library through it.

if i use my current computer as an htpc and server for all my media, what would you recommend for the living room? Centon Echo, or build another htpc?