When I tithe to the parish how is that money used and does any of this go to the poor and needy or does it just used for expenses to for administration and parish missions?
It depends on what you are giving the money to. There are usually some special collections for things like the missions, charity programs, St. Vincent de Paul, etc. Those special collections mean that the money from those collections is only used for that purpose.
The general weekly collection (aka “the weekly budget”) is a general fund that is used for administrative purposes as well as any charitable endeavor that the pastor wishes to engage in. Its primary purpose is the “brick and mortar” expenses of running the parish, without it the parish closes and nothing takes place. However what’s left over after usual expenses is certainly used for general charitable purposes.