You can do All-Grain the way you have described. You generally will get a lower efficiency since you won't be able to sparge the grains with as much water, but people do all-grain and top up, but not many.
You'll need to re-calculate your recipe to account for a lower hop utilization and lower efficiency.
What you did with the current batch should work out just fine. You may have slightly less hop utilization but it sounds like you boiled the hops with a good percentage of the batch so you should be fine.
"People should not be afraid of their governments. Governments should be afraid of their people." - V
Secondary: Shady Lord RIS, Water to Barleywine, Pumpkin wine, burnt mead
Kegged: Crappy infected mild
Bottles: Apfelwein, 999 Barleywine, Oatmeal Stout, Robust Porter, Robust smoked porter, Simcoe Smash