Since you have an HTIB, I would suggest
1. Get a good subwoofer first and add it to your HTIB, instant bass heaven ka na agad. I would blow my 25K on the sub alone hehehe you wont regret it...
2. Then get the receiver, you can use the HTIB speakers as long as you set the speakers to small
3. Then add the fronts,center and rears when funds allow