There should be some more numbers on the board.
Probably between the expansion slots or near the edges.
If you notice a "FEW" capacitors blown then there may be a more serious issue with the board or in rare cases the power supply itself.
A replacement board would in this case be a lot cheaper than the cost involved with a repair.
Luckily quite a few boards would fit in that case.
From a persona point of view and the fact that do do seem to have some damage it is reasonable to expect more damage to possibly the CPU itself or the RAM and maybe even other components.
To reduce the costs and provided you have both the time and some experience you may want to look at building a new machine
Cases are quite cheap and offer more expansion facilities than the acer one.
A new motherboard with CPU can also be had quite cheaply
Or you could even consider what is knows as a bare bones system.
Using that type of approach you could build the system and try the ram from your old one and if that is fine use it. Same with other internal devices.
As for the operating system if you have a proper copy of the operating system you could use it to install on a newer computer using the COA (Certificate of Authenticity) from the old one.
If you only have restore Cd's then it would be problematic (but not impossible)
I have found staples to be a little expensive for repairs so may tend to look at some of the smaller more reputable tech shops in your area.
Without more numbers etc from the boara it will be difficult to make an exact specification or suggest the nearest board.
A check on ebay may give you a few sources