I have been prescribed Ferrous Sulfate 325 mg. I have Feosol 45 mg?

No, as already pointed out this is way too much.
The Ferrous sulfate tablets you have been prescribed contain 65 mg of elemental iron.
Feosol tablets contain 45mg of elemental iron.
You are best to take 1 to 2 Feosol tablets daily to get a similar dose of iron that you have been prescribed from the ferrous sulfate tablets.
(It is probably best not to cut the Feosol tablets in half as they probably have a special outer coating which you ruin if the tablets are cut in half)

Don't take that many without clearing it with the doctor or pharmacist. Doctors prescribe certain supplements that they are familiar with, you can probably take the 45 mg feosol in place of the 325 ferrous sulfate at the normal 45 mg strength. Call you doctor and ask, tell him you already have the Feosol. Taking 7 is probably going to be too much.