How to get Textbox value in a multiple item Gridview Templatefield

Currently I have a Gridview that uses the following TemplateField:

                    <ItemTemplate>

                        <asp:TextBox  ID="txtRangeFrom" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "ScoreRangeLow") %>' >

                        </asp:TextBox>

                        &nbsp;<label for="to">To&nbsp;</label>

                        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<asp:TextBox  ID="txtRangeTo" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "ScoreRangeHigh") %>' >

                        </asp:TextBox>

                    </ItemTemplate>

When trying to update my datasource I have the issue that I can't read the values stored in the Datasource. How can I programatically access the values in the grid as well as the values stored in other controls inside a particular cell?