请教一个商品高级搜索代码的修改

下面是一段商品高级搜索代码:里面按商品价格搜索的范围是:100元以下\200元以下\300元以下\500元以下和不限制价格.
请问我想把它功能改为:100元以下\200至300元(不包括300元)\300至500元(不包括500元)\不限制价格.
那我应该怎样修改这段代码呢?
<!--#include file="conn.asp"-->
<!--#include file="webconfig.asp"-->
<!--#include file="fuction.asp"-->
<table width="100%" border="0" align="center" cellpadding="0" cellspacing="0" bgcolor="#FFFFFF">
                  <tr>
                    <td bgcolor="#000000"><form name="form2" method="post" action="research.asp">
                        <table width="100%"  border="0" align="center" cellpadding="2" cellspacing="5">
                          <tr bgcolor="333333">
                            <td colspan="2"><strong> </strong><b>商品高级搜索</b></td>
                          </tr>
                          <tr>
                            <td width="17%"><div align="right">关健字：</div></td>
                            <td><input name="searchkey" type="text" id="searchkey3" class="wenbenkuang"style="border:1px solid #5B6B7A; font-size:10pt;font-family:verdana;color:#BAE309;background-color:#000000"></td>
                          </tr>
                          <tr>
                            <td><div align="right">查找方式：</div></td>
                            <td  width="83%"><select style="border:1px solid #FF0000; FONT-SIZE: 9pt; COLOR:  #BAE309; BACKGROUND-COLOR: #333333"name="action" id="select" onChange="showselect();" class="wenbenkuang">
                                <option value="1" selected>商品名称</option>
                                
                              </select>
                            </td>
                          </tr>
                          <tr>
                            <td><div align="right">价格范围：</div></td>
                            <td><select name="jiage" id="select2" class="wenbenkuang">                                <option style="border:1px solid #FF0000; FONT-SIZE: 9pt; COLOR:  #BAE309; BACKGROUND-COLOR: #333333" value="100">100元以下</option>
    <option style="border:1px solid #FF0000; FONT-SIZE: 9pt; COLOR:  #BAE309; BACKGROUND-COLOR: #333333" value="200">200元以下</option>
<option style="border:1px solid #FF0000; FONT-SIZE: 9pt; COLOR:  #BAE309; BACKGROUND-COLOR: #333333" value="300">300元以下</option>
    <option style="border:1px solid #FF0000; FONT-SIZE: 9pt; COLOR:  #BAE309; BACKGROUND-COLOR: #333333" value="500">500元以下</option>
                                <option style="border:1px solid #FF0000; FONT-SIZE: 9pt; COLOR:  #BAE309; BACKGROUND-COLOR: #333333" value="1000000000" selected>不限制价格</option>
                            </select></td>
                          </tr>
                          <tr>
                            <td><div align="right">商品分类：</div></td>
                            <td><%set rs=server.CreateObject("adodb.recordset")
  rs.open "select * from shop_anclass order by anclassidorder",conn,1,1
  %>
                                <select name="anclassid" class="wenbenkuang">
                                  <option style="border:1px solid #FF0000; FONT-SIZE: 9pt; COLOR:  #BAE309; BACKGROUND-COLOR: #333333" value="0">查询所有分类</option>
                                  <%do while not rs.eof%>
                                  <option style="border:1px solid #FF0000; FONT-SIZE: 9pt; COLOR:  #BAE309; BACKGROUND-COLOR: #333333" value="<%=rs("anclassid")%>"><%=trim(rs("anclass"))%></option>
                                  <%rs.movenext
  loop
  rs.close
  set rs=nothing%>
                                </select>
                            </td>
                          </tr>
                          <tr>
                            <td colspan="2"><div align="left"> 　　　　　　
                                    <input name="Submit2" type="submit" class="go-wenbenkuang" value="提交查询" >
                                    <input name="Submit2" type="reset" class="go-wenbenkuang" value="重置">
                            </div></td>
                          </tr>
                        </table>
                    </form></td>
                  </tr>
              </table>